DataDog · AlexeyKuznetsov-DD · May 28, 2025 · May 20, 2025 · May 20, 2025 · May 23, 2025
@@ -17,8 +17,34 @@ configurations {
   traceShadowInclude
 }
 
-sourceCompatibility = JavaVersion.VERSION_1_7
-targetCompatibility = JavaVersion.VERSION_1_7
+// Support SSI inject for Java 7.
+tasks.named("compileJava", JavaCompile).configure {
+  sourceCompatibility = JavaVersion.VERSION_1_7
+  targetCompatibility = JavaVersion.VERSION_1_7
+}
+
+// Support SSI inject for Java 6.
+sourceSets {
+  java6 {
+    java {
+      srcDirs = ['src/main/java6']
+    }
+  }
+}
+
+tasks.register('compileJava6', JavaCompile) {
+  classpath = sourceSets.main.compileClasspath
+  source = sourceSets.java6.java
+  destinationDirectory = layout.buildDirectory.dir("classes/java/main")
+  sourceCompatibility = JavaVersion.VERSION_1_6
+  targetCompatibility = JavaVersion.VERSION_1_6
+}
+
+dependencies {
+  java6CompileOnly 'de.thetaphi:forbiddenapis:3.4'
+}
+
+    tasks.compileJava.dependsOn compileJava6
 
 /*
  * Several shadow jars are created
@@ -68,7 +94,7 @@ ext.generalShadowJarConfig = {
   if (!projectName.equals('instrumentation')) {
     relocate 'org.yaml.snakeyaml', 'datadog.snakeyaml'
     relocate 'okhttp3', 'datadog.okhttp3'
-    relocate 'okio',  'datadog.okio'
+    relocate 'okio', 'datadog.okio'
   }
 
   if (!project.hasProperty("disableShadowRelocate") || !disableShadowRelocate) {
@@ -176,7 +202,7 @@ shadowJar generalShadowJarConfig >> {
     attributes(
       "Main-Class": "datadog.trace.bootstrap.AgentBootstrap",
       "Agent-Class": "datadog.trace.bootstrap.AgentBootstrap",
-      "Premain-Class": "datadog.trace.bootstrap.AgentBootstrap",
+      "Premain-Class": "datadog.trace.bootstrap.AgentBootstrapJava6",
       "Can-Redefine-Classes": true,
       "Can-Retransform-Classes": true,
       )

diff --git a/dd-java-agent/src/main/java6/datadog/trace/bootstrap/AgentBootstrapJava6.java b/dd-java-agent/src/main/java6/datadog/trace/bootstrap/AgentBootstrapJava6.java
@@ -0,0 +1,156 @@
+package datadog.trace.bootstrap;
+
+import de.thetaphi.forbiddenapis.SuppressForbidden;
+import java.io.BufferedReader;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+import java.io.OutputStream;
+import java.lang.instrument.Instrumentation;
+import java.lang.reflect.Method;
+
+/** Special lightweight pre-main class to enable SSI inject for Java 6. */
+public class AgentBootstrapJava6 {
+  public static void premain(final String agentArgs, final Instrumentation inst) {
+    agentmain(agentArgs, inst);
+  }
+
+  public static void agentmain(final String agentArgs, final Instrumentation inst) {
+    try {
+      String version = System.getProperty("java.version");
+      // Found Java 6
+      if (version.startsWith("1.6")) {
+        reportUnsupportedJava6(version);
+      } else {
+        continueBootstrap(agentArgs, inst);
+      }
+    } catch (Throwable e) {
+      error("Agent pre-main function failed", e);
+    }
+  }
+
+  private static void error(String msg, Throwable e) {
+    log(msg + ": " + e.getMessage());
+  }
+
+  @SuppressForbidden
+  private static void log(String msg) {
+    // We don't have a log manager here, so just print.
+    System.out.println(msg);
+  }
+
+  public static void reportUnsupportedJava6(String javaVersion) {
+    try {
+      String agentVersion = getAgentVersion();
+      log(
+          "Warning: "
+              + agentVersion
+              + " of dd-java-agent is not compatible with Java "
+              + javaVersion
+              + " and will not be installed.");
+      log("Please upgrade your Java version to 8+");
+      String forwarderPath = null;
+      try {
+        forwarderPath = System.getenv("DD_TELEMETRY_FORWARDER_PATH");
+      } catch (SecurityException e) {
+        log("Failed to get DD_TELEMETRY_FORWARDER_PATH: " + e.getMessage());
+      }
+      if (forwarderPath == null) {
+        log("Telemetry forwarder path is null.");
+        return;
+      }
+      String payload =
+          "{\"metadata\":{"
+              + "\"runtime_name\":\"jvm\","
+              + "\"language_name\":\"jvm\","
+              + "\"runtime_version\":\""
+              + javaVersion
+              + "\","
+              + "\"language_version\":\""
+              + javaVersion
+              + "\","
+              + "\"tracer_version\":\""
+              + agentVersion
+              + "\"},"
+              + "\"points\":\"[{"
+              + "\"name\":\"library_entrypoint.abort\","
+              + "\"tags\":[\"reason:incompatible_runtime\"]"
+              + "}]"
+              + "}";
+
+      ForwarderJsonSenderThread t = new ForwarderJsonSenderThread(forwarderPath, payload);
+      t.start();
+
+      try {
+        t.join(1000);
+      } catch (InterruptedException e) {
+        // just for hygiene, reset the interrupt status
+        Thread.currentThread().interrupt();
+      }
+    } catch (Throwable e) {
+      error("Failed to report telemetry", e);
+    }
+  }
+
+  public static String getAgentVersion() {
+    try {
+      // Get the resource as an InputStream
+      InputStream is = AgentBootstrapJava6.class.getResourceAsStream("/dd-java-agent.version");
+      if (is == null) {
+        return "n/a";
+      }
+
+      BufferedReader reader = new BufferedReader(new InputStreamReader(is));
+      final StringBuilder sb = new StringBuilder();
+      for (int c = reader.read(); c != -1; c = reader.read()) {
+        sb.append((char) c);
+      }
+      reader.close();
+
+      return sb.toString().trim();
+    } catch (Throwable e) {
+      return "unknown";
+    }
+  }
+
+  @SuppressForbidden
+  private static void continueBootstrap(final String agentArgs, final Instrumentation inst) {
+    try {
+      Class<?> clazz = Class.forName("datadog.trace.bootstrap.AgentBootstrap");
+      Method agentMain = clazz.getMethod("agentmain", String.class, Instrumentation.class);
+      agentMain.invoke(null, agentArgs, inst);
+    } catch (Throwable e) {
+      System.err.println("Failed to install dd-java-agent: " + e.getMessage());
+    }
+  }
+
+  public static final class ForwarderJsonSenderThread extends Thread {
+    private final String forwarderPath;
+    private final String payload;
+
+    public ForwarderJsonSenderThread(String forwarderPath, String payload) {
+      super("dd-forwarder-json-sender");
+      setDaemon(true);
+      this.forwarderPath = forwarderPath;
+      this.payload = payload;
+    }
+
+    @Override
+    public void run() {
+      ProcessBuilder builder = new ProcessBuilder(forwarderPath, "library_entrypoint");
+      try {
+        Process process = builder.start();
+        OutputStream out = null;
+        try {
+          out = process.getOutputStream();
+          out.write(payload.getBytes());
+        } finally {
+          if (out != null) {
+            out.close();
+          }
+        }
+      } catch (Throwable e) {
+        error("Failed to send telemetry", e);
+      }
+    }
+  }
+}