How Java Works

Thinking

Java’s unique strength lies in its combination of compilation and interpretation.

Understanding this process clarifies how Java achieves platform independence and efficient execution.

Java programs go through two key stages before execution:

Compilation: Java source code (.java files) is compiled by the Java compiler (javac) into platform-independent bytecode (.class files).
Interpretation: The JVM interprets or just-in-time compiles the bytecode into machine code specific to the host operating system and hardware at runtime.

This two-step process allows Java code to be written once and run anywhere with a compatible JVM.

Detailed explanation of Java's compilation and interpretation.


// Compile source code to bytecode
javac MyProgram.java

// Run bytecode with JVM
java MyProgram

This shows the two-step process: compiling source code into bytecode, then interpreting bytecode to run on any platform.

Java’s compilation and interpretation process enables software to run on Windows, Mac, Linux, and more without modification.

Android uses a similar bytecode process (Dalvik/ART) for running apps efficiently on diverse devices.

Java EE platforms benefit from this process to deploy scalable applications across various servers.

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The Java compiler converts source code (.java) into platform-independent bytecode (.class) files.

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JVM interprets bytecode to machine code specific to the host OS and hardware, allowing the same bytecode to run anywhere.

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Compilation transforms source code into bytecode before runtime, while interpretation translates bytecode into machine code during execution.

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No. Bytecode requires a JVM to interpret or compile it to machine code for execution.