Array Concept in java

Array Definition:

        Array is an variable that holds multiple values of same data type.

How to get array length in java? 

array length Definition: 

arr.length give the length of the array where arr is the array name.

Syntax:

arrayname.length;

Array simple Program: 

package array_pack;

class arr

{

      private int arr[] = new int[2];

      public void array_init()

      {

      arr[0] = 1;

      arr[1] = 2;

      }

      public void array_print()

      {

      for(int i = 0; i<arr.length; i++)

      System.out.println(arr[i]);

      }

}

public class arr_process {

      public static void main (String args[])

      {

            arr a = new arr();

            a.array_init();

            a.array_print();

      }

}

Output: 

1

2

Explanation: 

           First the program creates the instance for the class arr..Now with the help of the instance we are calling the array_init() function and array_print() function.

Note :

arr.length give the length of the array where arr is the array name.

Tags:

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Static Concepts in java

Static Definition:

        In classes, a static method is one that is called without an instance of that class(object), while a non-static method is called by instances of the class(object).  

Static Program: 

package static_pack;

public class stat {

      static int i = 12;

      int j = 20;

      static

      {

            subclass sub = new subclass();

            System.out.println("The Static value is: " +i);

            //System.out.println("The Static value is: " +j);

           

            sub.display();

      }

      public static void main(String[] args)

      {

            System.out.println("Oops Main class after static block...");

            subclass.print();

      }

}

create a subclass class in the same package:

package static_pack;

public class subclass

{

      static void print()

      {

            System.out.println("In Subclass static method");

      }

      public void display()

      {

            System.out.println("Static yaar!!");

      }

}

Output:-

The Static value is: 12

Static yaar!!

Oops Main class after static block...

In Subclass static method

Explanation :

                 From the above program u can understand that Static block gets executed before the public static void main(String args[]). The static block gets executed and then the main block gets executed

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A Simple Hello World Program in Java

To run a simple hello world program in java First we need to write the program in the notepad
as give below:

Step1:

Class Helloworld{
   public static void main(String args[])
   {
System.out.println("Hello World..!");
   }
}

Step2:
Save it with the file name Helloworld.java[The File name must be the name of the class].

Step 3:
Compile the program in command prompt(cmd)javac HelloWorld.java is used to compile the source code
Note:
When u compile the program it will create a byte-code file name Helloworld.class

Step 4:
Run the program in comand Prompt(cmd)
java HelloWorld
Note:
Now the byte code is excected in java interpreter with the command given above

Output of the Program :
Hello World..!

Tags:
          simple java Program,java,class,bycode,interpreter,source code,.java