Compile the simple program in java program

Simple Java Program for beginners (The HelloWorld.java) Java is powerful programming language and it is used to develop robust applications. Writing a simple Hello World program is stepwise step. This short example shows how to write first java application and compile and run it. I am assuming that latest version of JDK is installed on your machine HelloWorld.java - the source code for the "Hello, world!" program class HelloWorld { public static void main(String[] args) { System.out.println("Hello World!"); } } How to save To run this program, save it in a file with the name HelloWorld.java. It must be sure that the file name must match the name of the class. Compile the program javac HelloWorld.java command is used to compile the source code. When you compile the program you'll create a byte-code file named HelloWorld.class. You can confirm this with the dir command in the DOS/Windows world. Execute the byte code Now you can execute the byte code in the Java interpreter with this command: java HelloWorld Output of the program When you run the program at the command line, you'll see this output Hello, world! Understanding the HelloWorld.java code Let's examine the HelloWorld.java file. Class is the basic building block of the java program, java codes are written in the java class. class HelloWorld{ //Java Codes } Java codes are saved in the same name as the class name.java, so we have saved the file with the name "HelloWorld.java". There is one method public static void main (String[] args) which is necessary to for any class to be runnable. This function is the entry point of the execution. And the code System.out.println("Hello World!"); actually writes the Hello World! on the screen

Internal Architecture of JVM

Internal Architecture of JVM
Let's understand the internal architecture of JVM. It contains classloader, memory area, execution engine etc.


                
1) Classloader:

Classloader is a subsystem of JVM that is used to load class files.
2) Class(Method) Area:

Class(Method) Area stores per-class structures such as the runtime constant pool, field and method data, the code for methods.
3) Heap:

It is the runtime data area in which objects are allocated.
4) Stack:
Java Stack stores frames.It holds local variables and partial results, and plays a part in method invocation and return.
Each thread has a private JVM stack, created at the same time as thread.
A new frame is created each time a method is invoked. A frame is destroyed when its method invocation completes.
5) Program Counter Regiser:

PC (program counter) register. It contains the address of the Java virtual machine instruction currently being executed.
6) Native Method Stack:

It contains all the native methods used in the application.
7) Execution Engine:
It contains:
1) A virtual processor
2) Interpreter:Read bytecode stream then execute the instructions.
3) Just-In-Time(JIT) compiler:It is used to improve the performance.JIT compiles parts of the byte code that have similar functionality at the

same time, and hence reduces the amount of time needed for compilation.Here the term ?compiler? refers to a translator from the instruction set

of a Java virtual machine (JVM) to the instruction set of a specific CPU.

FORGET WINDOWS ADMINISTRATOR PASSWORD ???FOLLOW PASSWORD RECOVERY METHOD............

ERD COMMANDER DOWNLOAD FROM ANY WEBSITE

Download It From Any Website.
Extract The Rar File (Only If You Downloaded Rar Format), You Will Get .Iso File.
IF You Downloaded .Iso File ,Then Double Click.
Burn The .Iso File In CD. (Nero, Power-Iso Etc)









Insert CD And Restart
Make Sure CD –Rom Is At First Boot Device
Windows Will Start With ERD.