JavaScript

JavaScript is a dynamic language. This means that we can change the type of the values that our variable are holding anytime. The type of the values in Dynamic languages is set at runtime in relation to the value.

let name = 'Peter';
name = 2;
console.log(name); // 2

In static languages like JAVA, when we declare a variable we also assign its type. This prevents us to change the type of the value in the future. The type of the values in Static languages is set at compilation time.

String [] words  = {"Hi", "Hello"};
words = 1;

In this example, we are declaring the variable words, assigning as its type an array of strings and setting {"Hi", "Hello"} as its value. Then, we are trying to set 1 (which is an integer), resulting in the following error:

error: incompatible types: int cannot be converted to String[]