Difference Between Source Code and Byte Code in Java

In this blog post, we will discuss the difference between source code and byte code in Java.

1. What is a Source Code?

Source code is the human-readable code that developers write using a programming language. In Java, source code is written in .java files using the Java programming language's syntax. This code includes definitions of classes, methods, variables, and all the logic that constitutes a Java application. It's the code that programmers interact with, modify, and use to implement software functionalities.

2. What is Bytecode? 

Bytecode is the intermediate representation of your Java program after the source code has been compiled by the Java compiler (javac). This representation is platform-independent, meaning it can run on any device or operating system capable of running a Java Virtual Machine (JVM). Bytecode files have a .class extension and contain a series of instructions that the JVM understands and executes.

3. Difference Between Source Code and Byte Code in Java

Source Code Byte Code
Human-readable code written by developers in Java. Intermediate, machine-friendly code generated by the Java compiler.
Stored in .java files. Stored in .class files.
Needs to be compiled to become executable by the JVM. It is the compiled version of the source code, executable by the JVM.
Platform-dependent in the sense that it must be compiled for each specific JVM. Platform-independent, it can run on any device with a JVM.
Easy for humans to understand, modify, and debug. It is not meant to be read or modified by humans; it is difficult to debug directly.
Directly reflects the programmer’s intent, structure, and comments. Reflects the logical structure of the program in a standardized binary format.
Specific to the high-level programming language used (e.g., Java). Universal among Java environments, facilitating the “write once, run anywhere” (WORA) principle.

Understanding these differences highlights the transformation from human-readable Java source code to the JVM-friendly bytecode, showcasing the compilation process's role in making Java programs versatile and platform-independent.