Jvm
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The document discusses the Java Development Kit (JDK), Java Runtime Environment (JRE), and Java Virtual Machine (JVM). The JDK contains tools needed to develop Java programs like compilers and allows programs to run. The JRE includes the JVM and Java class libraries, and is needed to run Java programs. The JVM interprets Java bytecode from compiled .class files into machine code that can be executed by different operating systems and hardware. It loads classes and interfaces, executes methods, and manages a method area for class data and heap area for objects using shared memory across threads.
Jvm
- 2. What is JDK,JVM,JRE? JDK: Java Development Kit contains tools needed to develop java programs. the tools are(JAVAC.EXE=compiler , JAVA.EXE= how you start the JVM) applet viewer etc. JRE: JRE=JVM+Java packages(class libraries as util,math,lang,awt,swing...) Actually JVM runs the program, and it uses the class libraries, and other supporting files provided in JRE If you want to run any java program, you need to have JRE installed in the system JVM: JVM is an Interpreter When we compile a JAVA File, output is not an '.exe' but it's a '.class' file consist of Java Byte Codes Which are understandable by JVM. JVM Inteprets the bytecodes into the machine code depending on operating system and hardware combination
- 3. JVM
- 4. Description of jvm CL=loading classes and interfaces Execution Engine= executing the instruction contained in methods of loaded classes . Each instruction of JVM has one method area and one heap area . These area are shared by all thread running inside virtual machine Method Area= class data Heap Area= object PC Register= Thread 1 , Thread 2, Thread 3 Java Stacks= stack frame Native method= is a great way to gain and merge the power of C or C++ programming into Java