Java bytecode
- Snippet from Wikipedia: Java bytecode
Java bytecode is the instruction set of the Java virtual machine (JVM), crucial for executing programs written in the Java language and other JVM-compatible languages. Each bytecode operation in the JVM is represented by a single byte, hence the name "bytecode", making it a compact form of instruction. This intermediate form enables Java programs to be platform-independent, as they are compiled not to native machine code but to a universally executable format across different JVM implementations.
The JVM interprets this bytecode or compiles it on-the-fly into native machine code using a Just-In-Time (JIT) compiler, enhancing the performance of Java applications. The design of Java bytecode aims for a high degree of cross-platform compatibility and security, executed within the JVM's controlled environment. This architecture allows Java applications to run consistently across various hardware and software configurations. While Java programmers typically do not interact directly with bytecode, understanding its structure and execution can be advantageous for optimization and debugging purposes.
In the JVM, Java bytecode operates as a set of instructions for both a stack machine and a register machine, utilizing an operand stack and local variables for executing operations. The bytecode comprises various instruction types, including data manipulation, control transfer, object creation and manipulation, and method invocation, all integral to Java's object-oriented programming model.