Java virtual machine
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The Java Virtual Machine (JVM) is a software-based emulation of a computer that executes Java bytecode, which comprises opcodes and optional parameters. It facilitates the portability and security of Java applications and supports compilers for other programming languages, emphasizing a 'compile once, run anywhere' philosophy. The JVM handles class loading, memory management, and provides a comprehensive instruction set for various operations like arithmetic, object manipulation, and concurrency.
Java virtual machine
- 1. JAVA VIRTUAL MACHINE Dhanith Krishna
- 2. Virtual Machines A virtual machine (VM) is a software-based emulation of a computer. JVM executes Java byte code Byte code is one byte op-codes followed by optional parameters JVM platform is used by Python, Ruby etc code execution component of the Java platform
- 3. JVM Architecture •Better Security •Portability •Compile Once Run Anywhere NEED FOR JVM
- 4. IS JVM for JAVA alone ? • Compilers for other languages based on JVM exists • Assemblers on JVM •Erjang •Rhino •Free Pascal •Quercus •Jython •NetRexx •Jruby •Jacl
- 5. • Loads class to memory • Verification • Allocation of static fields • Linking • Invocation of initialization codes • Starting Main as a single thread • Additional Threads are created using Thread class How class file works in JVM ?
- 8. Storage Management Global Data – Global constant pool Contains program constants and symbol table information Per Thread Data – registers + stack + native stack Heap – Dynamically allocated memory
- 10. JVM Instruction Set •Load and store •Arithmetic •Type conversion •Object creation and manipulation •Operand stack management (push / pop) •Control transfer (branching) •Method invocation and return •Throwing exceptions •Monitor-based concurrency