BSc IT - Structure Programming Methodology - Java

Java is considered platform-independent because a Java program can run on any operating system (like Windows, macOS, or Linux) without needing to be rewritten or recompiled for that specific platform. This is possible because Java code is not directly converted into machine code like in other languages such as C or C++. Instead, it is compiled into an intermediate form called bytecode, which is executed by the Java Virtual Machine (JVM). Since every platform has its own JVM that understands this bytecode, the same Java program can run anywhere — giving Java the tagline: "Write Once, Run Anywhere."

## Steps of Java Program Execution:

1. **Writing the Code**: You write Java code in a file with a `.java` extension.
2. **Compilation**: The Java compiler (`javac`) compiles the code into **bytecode** and saves it in a `.class` file.
3. **Loading**: The **Class Loader** inside the JVM loads the `.class` file into memory.
4. **Verification**: The **Bytecode Verifier** checks if the bytecode is safe to run.
5. **Execution**: The **JVM interpreter** or Just-In-Time (JIT) compiler converts the bytecode into machine code at runtime and executes it.

So, as long as there's a JVM available for a particular system, that system can run Java programs — making Java platform-independent.