How Java Works ? (JDK,JRE,JVM)

Q . How Java Works ? (JDK,JVM,JRE)

--->    (In Short)

        1 )  JDK (Java Development Kit ) : 

     *  It Provides "Javac" Compiler Without "JDK" we can't Compiler our Source Code(.java)                             into Byte Code(.class) file for that we need JDK .

           

          2) JVM (Java Virtual Machine) :

      * It Excecutes Our Byte Code(.class) file in that "JVM"  Search for  PSVM(String args[])

         to Run the code:

    

           3) JRE (Java Runtime Enviroment) :

     * It Normally provides Libraries and various Components to our "JVM" Like an example

            (java.util,  java.lang). 


    ### Detailed Explaination : 


1. **Development with JDK**:

   - Write Java source code (`.java` files).

   - Use the JDK's `javac` compiler to compile the source code into bytecode (`.class` files).


2. **Execution with JRE (and JVM)**:

   - The JVM, part of the JRE, loads the compiled bytecode (`.class` files).

   - The JVM looks for the `main` method to start the program execution.

   - The JRE provides the necessary libraries and resources for the JVM to run the program.


###  Detailed Steps:

1. **Write Code**:

   - Developers write Java code in `.java` files.


2. **Compile Code**:

   - The `javac` compiler (part of the JDK) compiles the `.java` files into `.class` files containing Java bytecode.


3. **Run Code**:

   - The JVM (part of the JRE) reads and interprets the bytecode in the `.class` files.

   - The JVM searches for the `main` method with the correct signature to start the program.

   - The JVM executes the bytecode, using the libraries and resources provided by the JRE.


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