Introduction to the Java Virtual Machine 井民全

JVM (Java Virtual Machine) the environment in which the java programs execute The specification define an abstract computer, and the instructions, called bytecode Bytecode a byte-long instruction that the javac generates Java interpreter executes  Compiler compiles a.java file,  it produces a series of bycodes and stores them in a.class file.  The java interpreter can then execute the bytecodes stored in the.class file

Introduction Java is more than just a language; it is a computer environment design-time java (the java language) runtime java (the JVM) This machine can run Java The machine support the java runtime environment It implements a JVM

Introduction Java Virtual Specification a document which defines how to implement a JVM Implementation of Java Virtual Machine implementation of JVM follows this specification The JVM Specification is platform independent because, it can be implemented on any platform Specification: Java.sun.com/docs/books/vmspec/index.html

Introduction The JVM performs following functions Allocating memory for created objects Performing garbage collection Handing register and stack operations Calling on the host system for certain functions, such as device access Monitoring the security of apps

Reference: “ memory management, role of JVM ”, JBuilder Help: