diff --git a/jaehong/chapter1/build.gradle b/jaehong/chapter1/build.gradle
new file mode 100644
index 0000000..3cae2d7
--- /dev/null
+++ b/jaehong/chapter1/build.gradle
@@ -0,0 +1,19 @@
+plugins {
+    id 'java'
+}
+
+group 'org.example'
+version '1.0-SNAPSHOT'
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    testImplementation 'org.junit.jupiter:junit-jupiter-api:5.8.1'
+    testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine:5.8.1'
+}
+
+test {
+    useJUnitPlatform()
+}
\ No newline at end of file
diff --git a/jaehong/chapter1/docs/README.md b/jaehong/chapter1/docs/README.md
new file mode 100644
index 0000000..275cad2
--- /dev/null
+++ b/jaehong/chapter1/docs/README.md
@@ -0,0 +1,33 @@
+## 1. calcualtor라는 이름을 갖는 클래스를 텍스트 파일에 한번 만들어보자. 실제 코드를 여러분들이 만들어 실행하는 방법은 다음 장에서 배우니, 원하느 파일에 Clculator 클래스를 만들어보자.
+
+## 2. 본문에서 살펴본 더하기 외에 빼기, 곱하기, 나누기를 하고, 그 결과를 리턴해주는 메서드를 만들어보자
+
+### 1. 클래스가 뭔가요?
+
+클래스는 추상적인 표현으로는 상태(status) 와 행동을 (behavior) 를 가집니다. 자바에서는 변수(필드) 와 함수(메서드)를 가지고 있으며 자바 내에서 가장 작은 단위입니다.
+
+### 2. 메서드가 뭔가요?
+
+메서드는 자바 클래스내에 위치하고 있으며 재사용 가능한 기능입니다.
+
+### 3. 메서드의 매개 변수는 어디에 적어주나요?
+
+메서드의 매개변수는 자바 클래스 내부에 위치하고 있으며 타입과 이름을 필요로 합니다.
+
+```
+public class Example {
+    public int example( 여기에 위치합니다. )
+}
+```
+
+### 4. 메서드의 이름 앞에 꼭 적어 줘야 하는 건 뭐죠?
+
+메서드의 반환 타입을 필요로 합니다. 그 외에 접근 제어자가 붙을 수 있지만 기본적으로 명시하지 않으면 public입니다.
+
+### 5. 클래스가 갖고 있어야 한다고 한 두 가지가 뭐죠?
+
+클래스가 가지고 있어야 하는 것은 필드와 메서드입니다. 다른 말로는 상태와 행위가 있습니다.
+
+### 6. 메서드에서 결과를 돌려주려면 어떤 예약어를 사용해야 하나요?
+
+자바 메서드에서 결과를 돌려주기 위한 예약어는 `return` 을 사용해야 합니다.
\ No newline at end of file
diff --git a/jaehong/chapter1/gradle/wrapper/gradle-wrapper.jar b/jaehong/chapter1/gradle/wrapper/gradle-wrapper.jar
new file mode 100644
index 0000000..249e583
Binary files /dev/null and b/jaehong/chapter1/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/jaehong/chapter1/gradle/wrapper/gradle-wrapper.properties b/jaehong/chapter1/gradle/wrapper/gradle-wrapper.properties
new file mode 100644
index 0000000..ae04661
--- /dev/null
+++ b/jaehong/chapter1/gradle/wrapper/gradle-wrapper.properties
@@ -0,0 +1,5 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.5.1-bin.zip
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
diff --git a/jaehong/chapter1/gradlew b/jaehong/chapter1/gradlew
new file mode 100755
index 0000000..a69d9cb
--- /dev/null
+++ b/jaehong/chapter1/gradlew
@@ -0,0 +1,240 @@
+#!/bin/sh
+
+#
+# Copyright © 2015-2021 the original authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+##############################################################################
+#
+#   Gradle start up script for POSIX generated by Gradle.
+#
+#   Important for running:
+#
+#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
+#       noncompliant, but you have some other compliant shell such as ksh or
+#       bash, then to run this script, type that shell name before the whole
+#       command line, like:
+#
+#           ksh Gradle
+#
+#       Busybox and similar reduced shells will NOT work, because this script
+#       requires all of these POSIX shell features:
+#         * functions;
+#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+#         * compound commands having a testable exit status, especially «case»;
+#         * various built-in commands including «command», «set», and «ulimit».
+#
+#   Important for patching:
+#
+#   (2) This script targets any POSIX shell, so it avoids extensions provided
+#       by Bash, Ksh, etc; in particular arrays are avoided.
+#
+#       The "traditional" practice of packing multiple parameters into a
+#       space-separated string is a well documented source of bugs and security
+#       problems, so this is (mostly) avoided, by progressively accumulating
+#       options in "$@", and eventually passing that to Java.
+#
+#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
+#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
+#       see the in-line comments for details.
+#
+#       There are tweaks for specific operating systems such as AIX, CygWin,
+#       Darwin, MinGW, and NonStop.
+#
+#   (3) This script is generated from the Groovy template
+#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       within the Gradle project.
+#
+#       You can find Gradle at https://github.com/gradle/gradle/.
+#
+##############################################################################
+
+# Attempt to set APP_HOME
+
+# Resolve links: $0 may be a link
+app_path=$0
+
+# Need this for daisy-chained symlinks.
+while
+    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+    [ -h "$app_path" ]
+do
+    ls=$( ls -ld "$app_path" )
+    link=${ls#*' -> '}
+    case $link in             #(
+      /*)   app_path=$link ;; #(
+      *)    app_path=$APP_HOME$link ;;
+    esac
+done
+
+APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
+
+APP_NAME="Gradle"
+APP_BASE_NAME=${0##*/}
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD=maximum
+
+warn () {
+    echo "$*"
+} >&2
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+} >&2
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD=$JAVA_HOME/jre/sh/java
+    else
+        JAVACMD=$JAVA_HOME/bin/java
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD=java
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
+    case $MAX_FD in #(
+      max*)
+        MAX_FD=$( ulimit -H -n ) ||
+            warn "Could not query maximum file descriptor limit"
+    esac
+    case $MAX_FD in  #(
+      '' | soft) :;; #(
+      *)
+        ulimit -n "$MAX_FD" ||
+            warn "Could not set maximum file descriptor limit to $MAX_FD"
+    esac
+fi
+
+# Collect all arguments for the java command, stacking in reverse order:
+#   * args from the command line
+#   * the main class name
+#   * -classpath
+#   * -D...appname settings
+#   * --module-path (only if needed)
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if "$cygwin" || "$msys" ; then
+    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+
+    JAVACMD=$( cygpath --unix "$JAVACMD" )
+
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    for arg do
+        if
+            case $arg in                                #(
+              -*)   false ;;                            # don't mess with options #(
+              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+                    [ -e "$t" ] ;;                      #(
+              *)    false ;;
+            esac
+        then
+            arg=$( cygpath --path --ignore --mixed "$arg" )
+        fi
+        # Roll the args list around exactly as many times as the number of
+        # args, so each arg winds up back in the position where it started, but
+        # possibly modified.
+        #
+        # NB: a `for` loop captures its iteration list before it begins, so
+        # changing the positional parameters here affects neither the number of
+        # iterations, nor the values presented in `arg`.
+        shift                   # remove old arg
+        set -- "$@" "$arg"      # push replacement arg
+    done
+fi
+
+# Collect all arguments for the java command;
+#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
+#     shell script including quotes and variable substitutions, so put them in
+#     double quotes to make sure that they get re-expanded; and
+#   * put everything else in single quotes, so that it's not re-expanded.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -classpath "$CLASSPATH" \
+        org.gradle.wrapper.GradleWrapperMain \
+        "$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+    die "xargs is not available"
+fi
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
+#   set -- "${ARGS[@]}" "$@"
+#
+# but POSIX shell has neither arrays nor command substitution, so instead we
+# post-process each arg (as a line of input to sed) to backslash-escape any
+# character that might be a shell metacharacter, then use eval to reverse
+# that process (while maintaining the separation between arguments), and wrap
+# the whole thing up as a single "set" statement.
+#
+# This will of course break if any of these variables contains a newline or
+# an unmatched quote.
+#
+
+eval "set -- $(
+        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+        xargs -n1 |
+        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+        tr '\n' ' '
+    )" '"$@"'
+
+exec "$JAVACMD" "$@"
diff --git a/jaehong/chapter1/gradlew.bat b/jaehong/chapter1/gradlew.bat
new file mode 100644
index 0000000..f127cfd
--- /dev/null
+++ b/jaehong/chapter1/gradlew.bat
@@ -0,0 +1,91 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
+@if "%DEBUG%"=="" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%"=="" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if %ERRORLEVEL% equ 0 goto execute
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*
+
+:end
+@rem End local scope for the variables with windows NT shell
+if %ERRORLEVEL% equ 0 goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega
diff --git a/jaehong/chapter1/settings.gradle b/jaehong/chapter1/settings.gradle
new file mode 100644
index 0000000..ad555c3
--- /dev/null
+++ b/jaehong/chapter1/settings.gradle
@@ -0,0 +1,2 @@
+rootProject.name = 'chapter1'
+
diff --git a/jaehong/chapter1/src/main/java/org/example/Main.java b/jaehong/chapter1/src/main/java/org/example/Main.java
new file mode 100644
index 0000000..18a2006
--- /dev/null
+++ b/jaehong/chapter1/src/main/java/org/example/Main.java
@@ -0,0 +1,8 @@
+package org.example;
+
+
+public class Main {
+    public static void main(String[] args) {
+        System.out.println("Hello world!");
+    }
+}
\ No newline at end of file
diff --git a/jaehong/chapter1/src/main/java/org/example/component/Calculator.java b/jaehong/chapter1/src/main/java/org/example/component/Calculator.java
new file mode 100644
index 0000000..57d4106
--- /dev/null
+++ b/jaehong/chapter1/src/main/java/org/example/component/Calculator.java
@@ -0,0 +1,23 @@
+package org.example.component;
+
+public class Calculator {
+    public int add(int num1, int num2){
+        return num1 + num2;
+    }
+
+    public int addAll(int num1, int num2, int num3){
+        return add(add(num1, num2) , num3);
+    }
+
+    public int subtract(int num1, int num2){
+        return num1 - num2;
+    }
+
+    public int multiply(int num1, int num2){
+        return num1 * num2;
+    }
+
+    public int divide(int num1, int num2){
+        return num1 / num2;
+    }
+}
diff --git a/jaehong/chapter2/build.gradle b/jaehong/chapter2/build.gradle
new file mode 100644
index 0000000..3cae2d7
--- /dev/null
+++ b/jaehong/chapter2/build.gradle
@@ -0,0 +1,19 @@
+plugins {
+    id 'java'
+}
+
+group 'org.example'
+version '1.0-SNAPSHOT'
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    testImplementation 'org.junit.jupiter:junit-jupiter-api:5.8.1'
+    testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine:5.8.1'
+}
+
+test {
+    useJUnitPlatform()
+}
\ No newline at end of file
diff --git a/jaehong/chapter2/gradle/wrapper/gradle-wrapper.jar b/jaehong/chapter2/gradle/wrapper/gradle-wrapper.jar
new file mode 100644
index 0000000..249e583
Binary files /dev/null and b/jaehong/chapter2/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/jaehong/chapter2/gradle/wrapper/gradle-wrapper.properties b/jaehong/chapter2/gradle/wrapper/gradle-wrapper.properties
new file mode 100644
index 0000000..ae04661
--- /dev/null
+++ b/jaehong/chapter2/gradle/wrapper/gradle-wrapper.properties
@@ -0,0 +1,5 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.5.1-bin.zip
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
diff --git a/jaehong/chapter2/gradlew b/jaehong/chapter2/gradlew
new file mode 100755
index 0000000..a69d9cb
--- /dev/null
+++ b/jaehong/chapter2/gradlew
@@ -0,0 +1,240 @@
+#!/bin/sh
+
+#
+# Copyright © 2015-2021 the original authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+##############################################################################
+#
+#   Gradle start up script for POSIX generated by Gradle.
+#
+#   Important for running:
+#
+#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
+#       noncompliant, but you have some other compliant shell such as ksh or
+#       bash, then to run this script, type that shell name before the whole
+#       command line, like:
+#
+#           ksh Gradle
+#
+#       Busybox and similar reduced shells will NOT work, because this script
+#       requires all of these POSIX shell features:
+#         * functions;
+#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+#         * compound commands having a testable exit status, especially «case»;
+#         * various built-in commands including «command», «set», and «ulimit».
+#
+#   Important for patching:
+#
+#   (2) This script targets any POSIX shell, so it avoids extensions provided
+#       by Bash, Ksh, etc; in particular arrays are avoided.
+#
+#       The "traditional" practice of packing multiple parameters into a
+#       space-separated string is a well documented source of bugs and security
+#       problems, so this is (mostly) avoided, by progressively accumulating
+#       options in "$@", and eventually passing that to Java.
+#
+#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
+#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
+#       see the in-line comments for details.
+#
+#       There are tweaks for specific operating systems such as AIX, CygWin,
+#       Darwin, MinGW, and NonStop.
+#
+#   (3) This script is generated from the Groovy template
+#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       within the Gradle project.
+#
+#       You can find Gradle at https://github.com/gradle/gradle/.
+#
+##############################################################################
+
+# Attempt to set APP_HOME
+
+# Resolve links: $0 may be a link
+app_path=$0
+
+# Need this for daisy-chained symlinks.
+while
+    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+    [ -h "$app_path" ]
+do
+    ls=$( ls -ld "$app_path" )
+    link=${ls#*' -> '}
+    case $link in             #(
+      /*)   app_path=$link ;; #(
+      *)    app_path=$APP_HOME$link ;;
+    esac
+done
+
+APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
+
+APP_NAME="Gradle"
+APP_BASE_NAME=${0##*/}
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD=maximum
+
+warn () {
+    echo "$*"
+} >&2
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+} >&2
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD=$JAVA_HOME/jre/sh/java
+    else
+        JAVACMD=$JAVA_HOME/bin/java
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD=java
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
+    case $MAX_FD in #(
+      max*)
+        MAX_FD=$( ulimit -H -n ) ||
+            warn "Could not query maximum file descriptor limit"
+    esac
+    case $MAX_FD in  #(
+      '' | soft) :;; #(
+      *)
+        ulimit -n "$MAX_FD" ||
+            warn "Could not set maximum file descriptor limit to $MAX_FD"
+    esac
+fi
+
+# Collect all arguments for the java command, stacking in reverse order:
+#   * args from the command line
+#   * the main class name
+#   * -classpath
+#   * -D...appname settings
+#   * --module-path (only if needed)
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if "$cygwin" || "$msys" ; then
+    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+
+    JAVACMD=$( cygpath --unix "$JAVACMD" )
+
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    for arg do
+        if
+            case $arg in                                #(
+              -*)   false ;;                            # don't mess with options #(
+              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+                    [ -e "$t" ] ;;                      #(
+              *)    false ;;
+            esac
+        then
+            arg=$( cygpath --path --ignore --mixed "$arg" )
+        fi
+        # Roll the args list around exactly as many times as the number of
+        # args, so each arg winds up back in the position where it started, but
+        # possibly modified.
+        #
+        # NB: a `for` loop captures its iteration list before it begins, so
+        # changing the positional parameters here affects neither the number of
+        # iterations, nor the values presented in `arg`.
+        shift                   # remove old arg
+        set -- "$@" "$arg"      # push replacement arg
+    done
+fi
+
+# Collect all arguments for the java command;
+#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
+#     shell script including quotes and variable substitutions, so put them in
+#     double quotes to make sure that they get re-expanded; and
+#   * put everything else in single quotes, so that it's not re-expanded.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -classpath "$CLASSPATH" \
+        org.gradle.wrapper.GradleWrapperMain \
+        "$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+    die "xargs is not available"
+fi
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
+#   set -- "${ARGS[@]}" "$@"
+#
+# but POSIX shell has neither arrays nor command substitution, so instead we
+# post-process each arg (as a line of input to sed) to backslash-escape any
+# character that might be a shell metacharacter, then use eval to reverse
+# that process (while maintaining the separation between arguments), and wrap
+# the whole thing up as a single "set" statement.
+#
+# This will of course break if any of these variables contains a newline or
+# an unmatched quote.
+#
+
+eval "set -- $(
+        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+        xargs -n1 |
+        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+        tr '\n' ' '
+    )" '"$@"'
+
+exec "$JAVACMD" "$@"
diff --git a/jaehong/chapter2/gradlew.bat b/jaehong/chapter2/gradlew.bat
new file mode 100644
index 0000000..f127cfd
--- /dev/null
+++ b/jaehong/chapter2/gradlew.bat
@@ -0,0 +1,91 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
+@if "%DEBUG%"=="" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%"=="" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if %ERRORLEVEL% equ 0 goto execute
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*
+
+:end
+@rem End local scope for the variables with windows NT shell
+if %ERRORLEVEL% equ 0 goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega
diff --git a/jaehong/chapter2/settings.gradle b/jaehong/chapter2/settings.gradle
new file mode 100644
index 0000000..b030ae0
--- /dev/null
+++ b/jaehong/chapter2/settings.gradle
@@ -0,0 +1,2 @@
+rootProject.name = 'chapter2'
+
diff --git a/jaehong/chapter2/src/main/java/org/example/Main.java b/jaehong/chapter2/src/main/java/org/example/Main.java
new file mode 100644
index 0000000..39983c9
--- /dev/null
+++ b/jaehong/chapter2/src/main/java/org/example/Main.java
@@ -0,0 +1,21 @@
+package org.example;
+
+import static java.lang.System.out;
+
+import java.io.Console;
+import java.util.Collections;
+import java.util.List;
+import jdk.internal.misc.SharedSecrets;
+
+public class Main {
+    public static void main(String[] args) {
+        final var console = System.console();
+        SharedSecrets.getJavaIOAccess().console();
+
+        if(console == null){
+            out.println("console is null");
+            return;
+        }
+        console.printf("hello");
+    }
+}
\ No newline at end of file
diff --git a/jaehong/chapter2/src/main/java/org/example/component/HelloGodOfJava.java b/jaehong/chapter2/src/main/java/org/example/component/HelloGodOfJava.java
new file mode 100644
index 0000000..20c9022
--- /dev/null
+++ b/jaehong/chapter2/src/main/java/org/example/component/HelloGodOfJava.java
@@ -0,0 +1,6 @@
+package org.example.component;
+
+public class HelloGodOfJava {
+
+
+}
diff --git a/jaehong/chapter3/Calculator.java b/jaehong/chapter3/Calculator.java
new file mode 100644
index 0000000..13a0da7
--- /dev/null
+++ b/jaehong/chapter3/Calculator.java
@@ -0,0 +1,11 @@
+public class Calculator{
+
+	public static void main(String ...args){
+		System.out.println("calculator class started");
+	}
+
+	public int add(int a, int b) {return a+b;}
+	public int substract(int a,int b) {return a - b;}
+	public int multiply(int a, int b) {return a * b;}
+	public int divide(int a, int b) {return a / b;}
+}
diff --git a/jaehong/chapter3/Car.class b/jaehong/chapter3/Car.class
new file mode 100644
index 0000000..4ffa0d4
Binary files /dev/null and b/jaehong/chapter3/Car.class differ
diff --git a/jaehong/chapter3/Car.java b/jaehong/chapter3/Car.java
new file mode 100644
index 0000000..8cc8262
--- /dev/null
+++ b/jaehong/chapter3/Car.java
@@ -0,0 +1,24 @@
+public class Car{ 
+	private int speed;
+	private int distance;
+	private String color;
+
+
+	public void speedUp(){
+		this.speed += 5;
+		// 
+	}
+
+	public void breakDown(){
+		this.speed -= 10;
+
+	}
+	
+	public int getCurrentSpeed(){
+		return speed;
+	}
+	@Override public String toString(){
+		return "hello";
+	}
+
+}
diff --git a/jaehong/chapter3/CarManager.class b/jaehong/chapter3/CarManager.class
new file mode 100644
index 0000000..525a3a5
Binary files /dev/null and b/jaehong/chapter3/CarManager.class differ
diff --git a/jaehong/chapter3/CarManager.java b/jaehong/chapter3/CarManager.java
new file mode 100644
index 0000000..ab191e2
--- /dev/null
+++ b/jaehong/chapter3/CarManager.java
@@ -0,0 +1,14 @@
+
+public class CarManager{
+
+	public static void main(String ...args){
+		// 앞으로 여기에 코드가 들어감
+		Car dogCar = new Car();
+		dogCar.speedUp();
+		dogCar.speedUp();
+
+		System.out.println(dogCar.getCurrentSpeed());
+		dogCar.breakDown();
+		System.out.println(dogCar.getCurrentSpeed());
+	}	
+}
diff --git a/jaehong/chapter3/Children.class b/jaehong/chapter3/Children.class
new file mode 100644
index 0000000..86e51f6
Binary files /dev/null and b/jaehong/chapter3/Children.class differ
diff --git a/jaehong/chapter3/Children.java b/jaehong/chapter3/Children.java
new file mode 100644
index 0000000..24f704c
--- /dev/null
+++ b/jaehong/chapter3/Children.java
@@ -0,0 +1,5 @@
+
+public class Children extends Parent{
+
+}
+
diff --git a/jaehong/chapter3/Initialize.class b/jaehong/chapter3/Initialize.class
new file mode 100644
index 0000000..51a7fc6
Binary files /dev/null and b/jaehong/chapter3/Initialize.class differ
diff --git a/jaehong/chapter3/Initialize.java b/jaehong/chapter3/Initialize.java
new file mode 100644
index 0000000..b6aa909
--- /dev/null
+++ b/jaehong/chapter3/Initialize.java
@@ -0,0 +1,10 @@
+
+public class Initialize{
+	private int a;
+	private int b;
+
+	public Initialize(){
+		this.a = 1;
+		System.out.println(b);
+	}	
+}
diff --git a/jaehong/chapter3/Parent.class b/jaehong/chapter3/Parent.class
new file mode 100644
index 0000000..a310282
Binary files /dev/null and b/jaehong/chapter3/Parent.class differ
diff --git a/jaehong/chapter3/Parent.java b/jaehong/chapter3/Parent.java
new file mode 100644
index 0000000..e39a4f5
--- /dev/null
+++ b/jaehong/chapter3/Parent.java
@@ -0,0 +1,3 @@
+public class Parent{
+
+}
diff --git a/jaehong/chapter3/Sample.js b/jaehong/chapter3/Sample.js
new file mode 100644
index 0000000..121e77f
--- /dev/null
+++ b/jaehong/chapter3/Sample.js
@@ -0,0 +1,8 @@
+
+class Sample{
+
+}
+
+const sample = new Sample();
+
+console.log(typeof sample);
diff --git "a/jaehong/chapter5/\"Sample.java\"" "b/jaehong/chapter5/\"Sample.java\""
new file mode 100644
index 0000000..e69de29
diff --git a/jaehong/chapter5/--help b/jaehong/chapter5/--help
new file mode 100644
index 0000000..e69de29
diff --git a/jaehong/chapter5/<classes> b/jaehong/chapter5/<classes>
new file mode 100644
index 0000000..e69de29
diff --git a/jaehong/chapter5/<options> b/jaehong/chapter5/<options>
new file mode 100644
index 0000000..e69de29
diff --git a/jaehong/chapter5/CompareInteger.java b/jaehong/chapter5/CompareInteger.java
new file mode 100644
index 0000000..5ebd10e
--- /dev/null
+++ b/jaehong/chapter5/CompareInteger.java
@@ -0,0 +1,12 @@
+public class CompareInteger{
+
+
+	public static void main(String...args){
+
+		Integer i;
+		if(i == 42){
+			System.out.println(42);
+
+		}
+	}
+}
diff --git a/jaehong/chapter5/Compiled b/jaehong/chapter5/Compiled
new file mode 100644
index 0000000..e69de29
diff --git a/jaehong/chapter5/Direction.class b/jaehong/chapter5/Direction.class
new file mode 100644
index 0000000..99af3be
Binary files /dev/null and b/jaehong/chapter5/Direction.class differ
diff --git a/jaehong/chapter5/OperatorCasting.java b/jaehong/chapter5/OperatorCasting.java
new file mode 100644
index 0000000..97bc3da
--- /dev/null
+++ b/jaehong/chapter5/OperatorCasting.java
@@ -0,0 +1,29 @@
+
+public class OperatorCasting{
+	public static void main(String ...args){
+		var operator = new OperatorCasting();
+		operator.casting();
+	}
+	
+	public void casting(){
+
+		byte byteValue = 127;
+		short shortValue = byteValue; 
+		
+		shortValue++;
+		System.out.println(shortValue);
+		
+		byteValue=(byte)shortValue;
+		
+		System.out.println(byteValue);
+
+		byte s1 = (byte)((int) 9);
+		byte s2 = (byte)((int) 10);
+
+		System.out.println(s1);
+		System.out.println(s2);
+		System.out.println(((byte) Long.MAX_VALUE));
+		
+		
+	}
+}
diff --git a/jaehong/chapter5/OperatorMultipleDivision.java b/jaehong/chapter5/OperatorMultipleDivision.java
new file mode 100644
index 0000000..9b41a6a
--- /dev/null
+++ b/jaehong/chapter5/OperatorMultipleDivision.java
@@ -0,0 +1,21 @@
+public class OperatorMultipleDivision{
+
+	public static void main(String...args){
+
+		OperatorMultipleDivision sample = new OperatorMultipleDivision();
+		sample.multipleDivision();
+	}
+
+	
+	public void multipleDivision(){
+
+		int intValue1 =5;
+		int intValue2 =10;
+		
+		int result = intValue1 * intValue2;
+		System.out.println(result);
+		result = intValue2 / intValue1;
+		System.out.println(result);
+
+	}
+}
diff --git a/jaehong/chapter5/OperatorPlusMinus.java b/jaehong/chapter5/OperatorPlusMinus.java
new file mode 100644
index 0000000..a67f600
--- /dev/null
+++ b/jaehong/chapter5/OperatorPlusMinus.java
@@ -0,0 +1,19 @@
+public class OperatorPlusMinus{
+
+	public static void main(String ...args){
+		OperatorPlusMinus sample = new OperatorPlusMinus();	
+		sample.additive();
+	}
+
+	public void additive(){
+		int intValue1 = 5;
+		int intValue2 = 10;
+		
+		int result=intValue1 + intValue2;
+		
+		System.out.println(result);
+		result = intValue2 - intValue1;
+		
+		System.out.println(result);
+	}
+}
diff --git a/jaehong/chapter5/OperatorTilde.java b/jaehong/chapter5/OperatorTilde.java
new file mode 100644
index 0000000..d667eb2
--- /dev/null
+++ b/jaehong/chapter5/OperatorTilde.java
@@ -0,0 +1,12 @@
+public class OperatorTilde{
+
+	public static void main(String ...args){
+		int num = 1;
+		int a = num++ + --num;
+		System.out.println(a);
+
+	
+		final var result = OperatorTilde > OperatorTilde;
+
+	}
+}
diff --git a/jaehong/chapter5/Sample b/jaehong/chapter5/Sample
new file mode 100644
index 0000000..e69de29
diff --git a/jaehong/chapter5/Sample$1.class b/jaehong/chapter5/Sample$1.class
new file mode 100644
index 0000000..0b0188f
Binary files /dev/null and b/jaehong/chapter5/Sample$1.class differ
diff --git a/jaehong/chapter5/Sample(); b/jaehong/chapter5/Sample();
new file mode 100644
index 0000000..e69de29
diff --git a/jaehong/chapter5/Sample.class b/jaehong/chapter5/Sample.class
new file mode 100644
index 0000000..d0ba55c
Binary files /dev/null and b/jaehong/chapter5/Sample.class differ
diff --git a/jaehong/chapter5/Sample.java b/jaehong/chapter5/Sample.java
new file mode 100644
index 0000000..f442c78
--- /dev/null
+++ b/jaehong/chapter5/Sample.java
@@ -0,0 +1,42 @@
+public class Sample{
+
+	public static void main(String...args){
+		System.out.println(ifStatement(Direction.TOP));
+		System.out.println(ifStatement(Direction.BOTTOM));
+		System.out.println(ifStatement(Direction.LEFT));
+		System.out.println(ifStatement(Direction.RIGHT));
+	}
+
+	public static int ifStatement(Direction dr){
+		if(dr == Direction.TOP){
+			return 1;
+		}
+		if(dr == Direction.BOTTOM){
+			return 2;
+		}
+		if(dr == Direction.LEFT){
+			return 3;
+		}
+		if(dr == Direction.RIGHT){
+			return 4;
+		}
+		return 0;
+	}
+
+	public static int switchStatement(Direction dr){
+		return switch(dr){
+			case TOP -> 1;
+			case BOTTOM -> 2;
+			case LEFT -> 3;
+			case RIGHT -> 4;
+		};
+	}
+}
+
+
+enum Direction{
+	TOP,
+	BOTTOM,
+	LEFT,
+	RIGHT;
+}
diff --git a/jaehong/chapter5/Usage: b/jaehong/chapter5/Usage:
new file mode 100644
index 0000000..e69de29
diff --git a/jaehong/chapter5/a b/jaehong/chapter5/a
new file mode 100644
index 0000000..b28731d
Binary files /dev/null and b/jaehong/chapter5/a differ
diff --git a/jaehong/chapter5/a.txt b/jaehong/chapter5/a.txt
new file mode 100644
index 0000000..29b622e
--- /dev/null
+++ b/jaehong/chapter5/a.txt
@@ -0,0 +1,207 @@
+Classfile /Users/jaehong/Documents/java-basic-1/jaehong/chapter5/Sample.class
+  Last modified 2023. 4. 17.; size 1046 bytes
+  SHA-256 checksum 0ed37afb8327701d44e6d0c60e64743dd2622cb7b80a8df03d84081ff0e419f9
+  Compiled from "Sample.java"
+public class Sample
+  minor version: 0
+  major version: 62
+  flags: (0x0021) ACC_PUBLIC, ACC_SUPER
+  this_class: #20                         // Sample
+  super_class: #2                         // java/lang/Object
+  interfaces: 0, fields: 0, methods: 4, attributes: 3
+Constant pool:
+   #1 = Methodref          #2.#3          // java/lang/Object."<init>":()V
+   #2 = Class              #4             // java/lang/Object
+   #3 = NameAndType        #5:#6          // "<init>":()V
+   #4 = Utf8               java/lang/Object
+   #5 = Utf8               <init>
+   #6 = Utf8               ()V
+   #7 = Fieldref           #8.#9          // java/lang/System.out:Ljava/io/PrintStream;
+   #8 = Class              #10            // java/lang/System
+   #9 = NameAndType        #11:#12        // out:Ljava/io/PrintStream;
+  #10 = Utf8               java/lang/System
+  #11 = Utf8               out
+  #12 = Utf8               Ljava/io/PrintStream;
+  #13 = Fieldref           #14.#15        // Direction.TOP:LDirection;
+  #14 = Class              #16            // Direction
+  #15 = NameAndType        #17:#18        // TOP:LDirection;
+  #16 = Utf8               Direction
+  #17 = Utf8               TOP
+  #18 = Utf8               LDirection;
+  #19 = Methodref          #20.#21        // Sample.ifStatement:(LDirection;)I
+  #20 = Class              #22            // Sample
+  #21 = NameAndType        #23:#24        // ifStatement:(LDirection;)I
+  #22 = Utf8               Sample
+  #23 = Utf8               ifStatement
+  #24 = Utf8               (LDirection;)I
+  #25 = Methodref          #26.#27        // java/io/PrintStream.println:(I)V
+  #26 = Class              #28            // java/io/PrintStream
+  #27 = NameAndType        #29:#30        // println:(I)V
+  #28 = Utf8               java/io/PrintStream
+  #29 = Utf8               println
+  #30 = Utf8               (I)V
+  #31 = Fieldref           #14.#32        // Direction.BOTTOM:LDirection;
+  #32 = NameAndType        #33:#18        // BOTTOM:LDirection;
+  #33 = Utf8               BOTTOM
+  #34 = Fieldref           #14.#35        // Direction.LEFT:LDirection;
+  #35 = NameAndType        #36:#18        // LEFT:LDirection;
+  #36 = Utf8               LEFT
+  #37 = Fieldref           #14.#38        // Direction.RIGHT:LDirection;
+  #38 = NameAndType        #39:#18        // RIGHT:LDirection;
+  #39 = Utf8               RIGHT
+  #40 = Fieldref           #41.#42        // Sample$1.$SwitchMap$Direction:[I
+  #41 = Class              #43            // Sample$1
+  #42 = NameAndType        #44:#45        // $SwitchMap$Direction:[I
+  #43 = Utf8               Sample$1
+  #44 = Utf8               $SwitchMap$Direction
+  #45 = Utf8               [I
+  #46 = Methodref          #14.#47        // Direction.ordinal:()I
+  #47 = NameAndType        #48:#49        // ordinal:()I
+  #48 = Utf8               ordinal
+  #49 = Utf8               ()I
+  #50 = Class              #51            // java/lang/IncompatibleClassChangeError
+  #51 = Utf8               java/lang/IncompatibleClassChangeError
+  #52 = Methodref          #50.#3         // java/lang/IncompatibleClassChangeError."<init>":()V
+  #53 = Utf8               Code
+  #54 = Utf8               LineNumberTable
+  #55 = Utf8               main
+  #56 = Utf8               ([Ljava/lang/String;)V
+  #57 = Utf8               StackMapTable
+  #58 = Utf8               switchStatement
+  #59 = Utf8               SourceFile
+  #60 = Utf8               Sample.java
+  #61 = Utf8               NestMembers
+  #62 = Utf8               InnerClasses
+{
+  public Sample();
+    descriptor: ()V
+    flags: (0x0001) ACC_PUBLIC
+    Code:
+      stack=1, locals=1, args_size=1
+         0: aload_0
+         1: invokespecial #1                  // Method java/lang/Object."<init>":()V
+         4: return
+      LineNumberTable:
+        line 1: 0
+
+  public static void main(java.lang.String...);
+    descriptor: ([Ljava/lang/String;)V
+    flags: (0x0089) ACC_PUBLIC, ACC_STATIC, ACC_VARARGS
+    Code:
+      stack=2, locals=1, args_size=1
+         0: getstatic     #7                  // Field java/lang/System.out:Ljava/io/PrintStream;
+         3: getstatic     #13                 // Field Direction.TOP:LDirection;
+         6: invokestatic  #19                 // Method ifStatement:(LDirection;)I
+         9: invokevirtual #25                 // Method java/io/PrintStream.println:(I)V
+        12: getstatic     #7                  // Field java/lang/System.out:Ljava/io/PrintStream;
+        15: getstatic     #31                 // Field Direction.BOTTOM:LDirection;
+        18: invokestatic  #19                 // Method ifStatement:(LDirection;)I
+        21: invokevirtual #25                 // Method java/io/PrintStream.println:(I)V
+        24: getstatic     #7                  // Field java/lang/System.out:Ljava/io/PrintStream;
+        27: getstatic     #34                 // Field Direction.LEFT:LDirection;
+        30: invokestatic  #19                 // Method ifStatement:(LDirection;)I
+        33: invokevirtual #25                 // Method java/io/PrintStream.println:(I)V
+        36: getstatic     #7                  // Field java/lang/System.out:Ljava/io/PrintStream;
+        39: getstatic     #37                 // Field Direction.RIGHT:LDirection;
+        42: invokestatic  #19                 // Method ifStatement:(LDirection;)I
+        45: invokevirtual #25                 // Method java/io/PrintStream.println:(I)V
+        48: return
+      LineNumberTable:
+        line 4: 0
+        line 5: 12
+        line 6: 24
+        line 7: 36
+        line 8: 48
+
+  public static int ifStatement(Direction);
+    descriptor: (LDirection;)I
+    flags: (0x0009) ACC_PUBLIC, ACC_STATIC
+    Code:
+      stack=2, locals=1, args_size=1
+         0: aload_0
+         1: getstatic     #13                 // Field Direction.TOP:LDirection;
+         4: if_acmpne     9
+         7: iconst_1
+         8: ireturn
+         9: aload_0
+        10: getstatic     #31                 // Field Direction.BOTTOM:LDirection;
+        13: if_acmpne     18
+        16: iconst_2
+        17: ireturn
+        18: aload_0
+        19: getstatic     #34                 // Field Direction.LEFT:LDirection;
+        22: if_acmpne     27
+        25: iconst_3
+        26: ireturn
+        27: aload_0
+        28: getstatic     #37                 // Field Direction.RIGHT:LDirection;
+        31: if_acmpne     36
+        34: iconst_4
+        35: ireturn
+        36: iconst_0
+        37: ireturn
+      LineNumberTable:
+        line 11: 0
+        line 12: 7
+        line 14: 9
+        line 15: 16
+        line 17: 18
+        line 18: 25
+        line 20: 27
+        line 21: 34
+        line 23: 36
+      StackMapTable: number_of_entries = 4
+        frame_type = 9 /* same */
+        frame_type = 8 /* same */
+        frame_type = 8 /* same */
+        frame_type = 8 /* same */
+
+  public static int switchStatement(Direction);
+    descriptor: (LDirection;)I
+    flags: (0x0009) ACC_PUBLIC, ACC_STATIC
+    Code:
+      stack=2, locals=1, args_size=1
+         0: getstatic     #40                 // Field Sample$1.$SwitchMap$Direction:[I
+         3: aload_0
+         4: invokevirtual #46                 // Method Direction.ordinal:()I
+         7: iaload
+         8: tableswitch   { // 1 to 4
+                       1: 48
+                       2: 52
+                       3: 56
+                       4: 60
+                 default: 40
+            }
+        40: new           #50                 // class java/lang/IncompatibleClassChangeError
+        43: dup
+        44: invokespecial #52                 // Method java/lang/IncompatibleClassChangeError."<init>":()V
+        47: athrow
+        48: iconst_1
+        49: goto          61
+        52: iconst_2
+        53: goto          61
+        56: iconst_3
+        57: goto          61
+        60: iconst_4
+        61: ireturn
+      LineNumberTable:
+        line 27: 0
+        line 28: 48
+        line 29: 52
+        line 30: 56
+        line 31: 60
+        line 27: 61
+      StackMapTable: number_of_entries = 6
+        frame_type = 40 /* same */
+        frame_type = 7 /* same */
+        frame_type = 3 /* same */
+        frame_type = 3 /* same */
+        frame_type = 3 /* same */
+        frame_type = 64 /* same_locals_1_stack_item */
+          stack = [ int ]
+}
+SourceFile: "Sample.java"
+NestMembers:
+  Sample$1
+InnerClasses:
+  static #41;                             // class Sample$1
diff --git a/jaehong/chapter5/class b/jaehong/chapter5/class
new file mode 100644
index 0000000..e69de29
diff --git a/jaehong/chapter5/for b/jaehong/chapter5/for
new file mode 100644
index 0000000..e69de29
diff --git a/jaehong/chapter5/from b/jaehong/chapter5/from
new file mode 100644
index 0000000..e69de29
diff --git a/jaehong/chapter5/ifStatement(Direction); b/jaehong/chapter5/ifStatement(Direction);
new file mode 100644
index 0000000..e69de29
diff --git a/jaehong/chapter5/int b/jaehong/chapter5/int
new file mode 100644
index 0000000..e69de29
diff --git a/jaehong/chapter5/javap b/jaehong/chapter5/javap
new file mode 100644
index 0000000..7467582
Binary files /dev/null and b/jaehong/chapter5/javap differ
diff --git a/jaehong/chapter5/list b/jaehong/chapter5/list
new file mode 100644
index 0000000..e69de29
diff --git a/jaehong/chapter5/main(java.lang.String...); b/jaehong/chapter5/main(java.lang.String...);
new file mode 100644
index 0000000..e69de29
diff --git a/jaehong/chapter5/of b/jaehong/chapter5/of
new file mode 100644
index 0000000..e69de29
diff --git a/jaehong/chapter5/options b/jaehong/chapter5/options
new file mode 100644
index 0000000..e69de29
diff --git a/jaehong/chapter5/possible b/jaehong/chapter5/possible
new file mode 100644
index 0000000..e69de29
diff --git a/jaehong/chapter5/public b/jaehong/chapter5/public
new file mode 100644
index 0000000..e69de29
diff --git a/jaehong/chapter5/static b/jaehong/chapter5/static
new file mode 100644
index 0000000..e69de29
diff --git a/jaehong/chapter5/switchStatement(Direction); b/jaehong/chapter5/switchStatement(Direction);
new file mode 100644
index 0000000..e69de29
diff --git a/jaehong/chapter5/untitled/build.gradle b/jaehong/chapter5/untitled/build.gradle
new file mode 100644
index 0000000..3cae2d7
--- /dev/null
+++ b/jaehong/chapter5/untitled/build.gradle
@@ -0,0 +1,19 @@
+plugins {
+    id 'java'
+}
+
+group 'org.example'
+version '1.0-SNAPSHOT'
+
+repositories {
+    mavenCentral()
+}
+
+dependencies {
+    testImplementation 'org.junit.jupiter:junit-jupiter-api:5.8.1'
+    testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine:5.8.1'
+}
+
+test {
+    useJUnitPlatform()
+}
\ No newline at end of file
diff --git a/jaehong/chapter5/untitled/gradle/wrapper/gradle-wrapper.jar b/jaehong/chapter5/untitled/gradle/wrapper/gradle-wrapper.jar
new file mode 100644
index 0000000..249e583
Binary files /dev/null and b/jaehong/chapter5/untitled/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/jaehong/chapter5/untitled/gradle/wrapper/gradle-wrapper.properties b/jaehong/chapter5/untitled/gradle/wrapper/gradle-wrapper.properties
new file mode 100644
index 0000000..ae04661
--- /dev/null
+++ b/jaehong/chapter5/untitled/gradle/wrapper/gradle-wrapper.properties
@@ -0,0 +1,5 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.5.1-bin.zip
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
diff --git a/jaehong/chapter5/untitled/gradlew b/jaehong/chapter5/untitled/gradlew
new file mode 100755
index 0000000..a69d9cb
--- /dev/null
+++ b/jaehong/chapter5/untitled/gradlew
@@ -0,0 +1,240 @@
+#!/bin/sh
+
+#
+# Copyright © 2015-2021 the original authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+##############################################################################
+#
+#   Gradle start up script for POSIX generated by Gradle.
+#
+#   Important for running:
+#
+#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
+#       noncompliant, but you have some other compliant shell such as ksh or
+#       bash, then to run this script, type that shell name before the whole
+#       command line, like:
+#
+#           ksh Gradle
+#
+#       Busybox and similar reduced shells will NOT work, because this script
+#       requires all of these POSIX shell features:
+#         * functions;
+#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+#         * compound commands having a testable exit status, especially «case»;
+#         * various built-in commands including «command», «set», and «ulimit».
+#
+#   Important for patching:
+#
+#   (2) This script targets any POSIX shell, so it avoids extensions provided
+#       by Bash, Ksh, etc; in particular arrays are avoided.
+#
+#       The "traditional" practice of packing multiple parameters into a
+#       space-separated string is a well documented source of bugs and security
+#       problems, so this is (mostly) avoided, by progressively accumulating
+#       options in "$@", and eventually passing that to Java.
+#
+#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
+#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
+#       see the in-line comments for details.
+#
+#       There are tweaks for specific operating systems such as AIX, CygWin,
+#       Darwin, MinGW, and NonStop.
+#
+#   (3) This script is generated from the Groovy template
+#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       within the Gradle project.
+#
+#       You can find Gradle at https://github.com/gradle/gradle/.
+#
+##############################################################################
+
+# Attempt to set APP_HOME
+
+# Resolve links: $0 may be a link
+app_path=$0
+
+# Need this for daisy-chained symlinks.
+while
+    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+    [ -h "$app_path" ]
+do
+    ls=$( ls -ld "$app_path" )
+    link=${ls#*' -> '}
+    case $link in             #(
+      /*)   app_path=$link ;; #(
+      *)    app_path=$APP_HOME$link ;;
+    esac
+done
+
+APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
+
+APP_NAME="Gradle"
+APP_BASE_NAME=${0##*/}
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD=maximum
+
+warn () {
+    echo "$*"
+} >&2
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+} >&2
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD=$JAVA_HOME/jre/sh/java
+    else
+        JAVACMD=$JAVA_HOME/bin/java
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD=java
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
+    case $MAX_FD in #(
+      max*)
+        MAX_FD=$( ulimit -H -n ) ||
+            warn "Could not query maximum file descriptor limit"
+    esac
+    case $MAX_FD in  #(
+      '' | soft) :;; #(
+      *)
+        ulimit -n "$MAX_FD" ||
+            warn "Could not set maximum file descriptor limit to $MAX_FD"
+    esac
+fi
+
+# Collect all arguments for the java command, stacking in reverse order:
+#   * args from the command line
+#   * the main class name
+#   * -classpath
+#   * -D...appname settings
+#   * --module-path (only if needed)
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if "$cygwin" || "$msys" ; then
+    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+
+    JAVACMD=$( cygpath --unix "$JAVACMD" )
+
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    for arg do
+        if
+            case $arg in                                #(
+              -*)   false ;;                            # don't mess with options #(
+              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+                    [ -e "$t" ] ;;                      #(
+              *)    false ;;
+            esac
+        then
+            arg=$( cygpath --path --ignore --mixed "$arg" )
+        fi
+        # Roll the args list around exactly as many times as the number of
+        # args, so each arg winds up back in the position where it started, but
+        # possibly modified.
+        #
+        # NB: a `for` loop captures its iteration list before it begins, so
+        # changing the positional parameters here affects neither the number of
+        # iterations, nor the values presented in `arg`.
+        shift                   # remove old arg
+        set -- "$@" "$arg"      # push replacement arg
+    done
+fi
+
+# Collect all arguments for the java command;
+#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
+#     shell script including quotes and variable substitutions, so put them in
+#     double quotes to make sure that they get re-expanded; and
+#   * put everything else in single quotes, so that it's not re-expanded.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -classpath "$CLASSPATH" \
+        org.gradle.wrapper.GradleWrapperMain \
+        "$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+    die "xargs is not available"
+fi
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
+#   set -- "${ARGS[@]}" "$@"
+#
+# but POSIX shell has neither arrays nor command substitution, so instead we
+# post-process each arg (as a line of input to sed) to backslash-escape any
+# character that might be a shell metacharacter, then use eval to reverse
+# that process (while maintaining the separation between arguments), and wrap
+# the whole thing up as a single "set" statement.
+#
+# This will of course break if any of these variables contains a newline or
+# an unmatched quote.
+#
+
+eval "set -- $(
+        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+        xargs -n1 |
+        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+        tr '\n' ' '
+    )" '"$@"'
+
+exec "$JAVACMD" "$@"
diff --git a/jaehong/chapter5/untitled/gradlew.bat b/jaehong/chapter5/untitled/gradlew.bat
new file mode 100644
index 0000000..f127cfd
--- /dev/null
+++ b/jaehong/chapter5/untitled/gradlew.bat
@@ -0,0 +1,91 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
+@if "%DEBUG%"=="" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%"=="" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if %ERRORLEVEL% equ 0 goto execute
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*
+
+:end
+@rem End local scope for the variables with windows NT shell
+if %ERRORLEVEL% equ 0 goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega
diff --git a/jaehong/chapter5/untitled/settings.gradle b/jaehong/chapter5/untitled/settings.gradle
new file mode 100644
index 0000000..cc6146c
--- /dev/null
+++ b/jaehong/chapter5/untitled/settings.gradle
@@ -0,0 +1,2 @@
+rootProject.name = 'untitled'
+
diff --git a/jaehong/chapter5/untitled/src/main/java/org/example/Main.java b/jaehong/chapter5/untitled/src/main/java/org/example/Main.java
new file mode 100644
index 0000000..0f872c1
--- /dev/null
+++ b/jaehong/chapter5/untitled/src/main/java/org/example/Main.java
@@ -0,0 +1,11 @@
+package org.example;
+
+public class Main {
+    public static void main(String[] args) {
+        Integer number1 = 1;
+        int 	number2 = 1;
+
+        Long long1 = 1L;
+        long long2 = 1L;
+    }
+}
\ No newline at end of file
diff --git a/jaehong/chapter5/untitled/src/main/java/org/example/MyInteger.java b/jaehong/chapter5/untitled/src/main/java/org/example/MyInteger.java
new file mode 100644
index 0000000..dcd87a4
--- /dev/null
+++ b/jaehong/chapter5/untitled/src/main/java/org/example/MyInteger.java
@@ -0,0 +1,25 @@
+package org.example;
+
+public class MyInteger {
+    private int value;
+
+    public MyInteger(int value) {
+        this.value = value;
+    }
+
+    public int intValue() {
+        return value;
+    }
+
+    public static MyInteger valueOf(int value) {
+        return new MyInteger(value);
+    }
+
+    public static MyInteger valueOf(Integer value) {
+        return new MyInteger(value.intValue());
+    }
+
+    public static int unbox(MyInteger myInteger) {
+        return myInteger.intValue();
+    }
+}
\ No newline at end of file
diff --git a/jaehong/chapter5/untitled/src/main/java/org/example/Sample.java b/jaehong/chapter5/untitled/src/main/java/org/example/Sample.java
new file mode 100644
index 0000000..d383fb6
--- /dev/null
+++ b/jaehong/chapter5/untitled/src/main/java/org/example/Sample.java
@@ -0,0 +1,14 @@
+package org.example;
+
+public class Sample{
+
+	public static void main(String...args){
+		Integer number1 = 1;
+		int 	number2 = 1;
+
+		Long long1 = 1L;
+		long long2 = 1L;
+
+
+	}
+}
diff --git a/jaehong/chapter5/use b/jaehong/chapter5/use
new file mode 100644
index 0000000..e69de29
diff --git a/jaehong/chapter5/void b/jaehong/chapter5/void
new file mode 100644
index 0000000..e69de29
diff --git a/jaehong/chapter5/{ b/jaehong/chapter5/{
new file mode 100644
index 0000000..e69de29
diff --git a/jaehong/chapter5/} b/jaehong/chapter5/}
new file mode 100644
index 0000000..e69de29
diff --git a/jaehong/chapter6/.Test.java.swp b/jaehong/chapter6/.Test.java.swp
new file mode 100644
index 0000000..c429b0e
Binary files /dev/null and b/jaehong/chapter6/.Test.java.swp differ
diff --git a/jaehong/chapter6/ControlIf.class b/jaehong/chapter6/ControlIf.class
new file mode 100644
index 0000000..6043cb3
Binary files /dev/null and b/jaehong/chapter6/ControlIf.class differ
diff --git a/jaehong/chapter6/ControlIf.java b/jaehong/chapter6/ControlIf.java
new file mode 100644
index 0000000..52dfe1f
--- /dev/null
+++ b/jaehong/chapter6/ControlIf.java
@@ -0,0 +1,19 @@
+public class ControlIf{
+
+	public static void main(String...args){
+
+		var control = new ControlIf();
+	}
+
+	public void ifStatement(){
+		if(true);
+		if(true);
+		if(true);
+		if(true);
+		if(true);
+		if(true);
+		if(true);
+		if(true);
+		if(true) System.out.println("It's true");
+	}
+}
diff --git a/jaehong/chapter6/Sample.c b/jaehong/chapter6/Sample.c
new file mode 100644
index 0000000..e216155
--- /dev/null
+++ b/jaehong/chapter6/Sample.c
@@ -0,0 +1,19 @@
+#include<stdio.h>
+
+int main(){
+
+	if(1){
+		printf("1 run \n");
+	}
+	if(3){
+		printf("3 run \n");
+	}
+	if(-1){
+		printf("-1 run \n");
+	}
+
+	if(0){
+		printf("0 run \n");
+	}
+	return 0;
+}
diff --git a/jaehong/chapter6/Sample.go b/jaehong/chapter6/Sample.go
new file mode 100644
index 0000000..5bc9898
--- /dev/null
+++ b/jaehong/chapter6/Sample.go
@@ -0,0 +1,9 @@
+package main
+
+import "fmt" 
+
+func main(){
+
+	fmt.println("hello world")
+
+}
diff --git a/jaehong/chapter6/Sample.java b/jaehong/chapter6/Sample.java
new file mode 100644
index 0000000..fb83aed
--- /dev/null
+++ b/jaehong/chapter6/Sample.java
@@ -0,0 +1,9 @@
+public class Sample{
+
+
+	public static void main(String...args){
+		if(3){
+			System.out.println("run");
+		}
+	}
+}
diff --git a/jaehong/chapter6/Sample.js b/jaehong/chapter6/Sample.js
new file mode 100644
index 0000000..bcd2e08
--- /dev/null
+++ b/jaehong/chapter6/Sample.js
@@ -0,0 +1,13 @@
+if(3){
+	console.log("3 run");
+}
+
+if(0){
+
+	console.log("0 run");
+}
+
+if(-1){
+
+	console.log("-1 run");
+}
diff --git a/jaehong/chapter6/a.out b/jaehong/chapter6/a.out
new file mode 100755
index 0000000..80961f9
Binary files /dev/null and b/jaehong/chapter6/a.out differ
diff --git a/jaehong/marp/Main.class b/jaehong/marp/Main.class
new file mode 100644
index 0000000..7838318
Binary files /dev/null and b/jaehong/marp/Main.class differ
diff --git a/jaehong/marp/Main.java b/jaehong/marp/Main.java
new file mode 100644
index 0000000..2ed05f6
--- /dev/null
+++ b/jaehong/marp/Main.java
@@ -0,0 +1,7 @@
+
+public class Main{
+	public static void main(String ...args){
+		System.out.println("Hello world");
+		new Sample();
+	}
+}
diff --git a/jaehong/marp/README.md b/jaehong/marp/README.md
new file mode 100644
index 0000000..cc6d435
--- /dev/null
+++ b/jaehong/marp/README.md
@@ -0,0 +1,24 @@
+---
+marp: true
+theme: gaia
+
+---
+
+# 토비의 스프링을 학습하고 무엇을 얻었는가
+
+---
+
+# 목차
+
+- 필사를 통해서 배운것
+- 스프링의 역사
+- 이번 스터디를 진행하면서 배운 것 들
+---
+
+# 필사를 통해서 배운것
+
+## 필사는 **책을 손으로 직접 베껴 쓰는 일** 입니다.
+![img.png](img.png)
+
+---
+
diff --git a/jaehong/marp/Sample.class b/jaehong/marp/Sample.class
new file mode 100644
index 0000000..6211b36
Binary files /dev/null and b/jaehong/marp/Sample.class differ
diff --git a/jaehong/marp/Sample.java b/jaehong/marp/Sample.java
new file mode 100644
index 0000000..3d028fe
--- /dev/null
+++ b/jaehong/marp/Sample.java
@@ -0,0 +1,8 @@
+
+public class Sample{
+	private final String id;
+
+	public Sample(){
+		id = "id";
+	}
+}
diff --git a/jaehong/marp/img.png b/jaehong/marp/img.png
new file mode 100644
index 0000000..96bb01d
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