Question

how can I check if this two dimentinal array is empty?

this is my code :

      String[][] user = new String[5][3];

        System.out.print(user.length);

            if (user.length == 5 ){
                System.out.print("\n empty");
            }

        for (int j=0; j<3; j++) {
            System.out.print(" " + user[0][j]+ "\n");
        }

and the output is :

5
 empty null null null

Does anyone have an ide about my situation?

Answer 1

You are misunderstanding something in Java I think. When you write :

String[][] user = new String[5][3];

user.length will always be 5 and 

user[0].length = user[1].length = ... = user[5].length = 3

If you want to check if all value in your array are emty you can do something like :

boolean notNull = false;
for(String[] array : user){
    for(String val : array){
      if(val!=null){
        notNull=true;
        break;
      }
    }
}
if(notNull){
  System.out.println("Array not empty)";
}else{
     System.out.println("Array empty");
}

Another solution would be to use Arrays.deepEquals :

String[][] user = new String[5][3];
String[][] emptyReferenceForComparison= new String[5][3];
Arrays.deepEquals(user, emptyReferenceForComparison); // return true