Can you explain the process of transforming source code into bytecode during compilation?

In Java, the process of converting source code into bytecode occurs during compilation using the javac compiler. The Java source code (.java files) is analyzed by the compiler, which checks syntax and semantics, and then converts it into bytecode — an intermediate representation stored in .class files.

Bytecode is a set of instructions understandable by the Java Virtual Machine (JVM). It is platform-independent, allowing the same bytecode to run on different operating systems and architectures where JVM is installed.

Example of a simple class and its compilation:

// HelloWorld.java
public class HelloWorld {
    public static void main(String[] args) {
        System.out.println("Hello, world!");
    }
}

Compilation command:

javac HelloWorld.java

As a result, a HelloWorld.class file with bytecode will be generated.

Thus, compilation is the process of transforming high-level code into bytecode, which is then executed by the JVM.