Three ways of array definition in Java

method one:

　　1. First declare 2. Allocate space 3. Assign

　　　

public  class arr{
     public  static  void main(String[] args){
             int [] arr;     //declare first
         arr= new  int [5];   //allocate space
         for ( int i=0;i<5;i++)arr [i]=i*10;   //Assign
         for ( int i=0;i<5;i++ ){
            System.out.println("arr["+i+"]="+arr[i]);
        }
    }
}

　　result:

　　

Method Two:

　　1. Declare and allocate space 2. Assign

public  class arr{
     public  static  void main(String[] args){
             int [] arr= new  int [5];     //declare and allocate space
             for ( int i=0;i<5;i++)arr[i]= i*10;     //Assign
         for ( int i=0;i<5;i++ ){
            System.out.println("arr["+i+"]="+arr[i]);
        }
    }
}    

Same result as above.

Method three:

　　1. Declare and allocate space then. Assign

public class arr{
    public static void main(String[] args){
            int[] arr={20,68,34,22,34}; //Declare and allocate space then. Assign 
        for ( int i=0;i<5;i++ ){
            System.out.println("arr["+i+"]="+arr[i]);
        }
    }
}

result: