我不能在其中输入高于9的值

Question

I think this works perfectly when I input values lower than 9. But whenever I input a value higher than 9, program throws ArrayIndexOutOfBoundsException. I cant figure out which causes this problem. Can someone simply explain me this problem and what is the solution for this?

import java.util.Scanner;
public class Main{
public static void main(String[] args) {
    int[][] twoDAarray = new int[3][3];

    Scanner input = new Scanner(System.in);
    System.out.println("Enter values: ");
    for(int i=0; i<3; i++){
        for(int j=0; j<3; j++){
            twoDAarray[i][j] = input.nextInt();
        }
    }

    System.out.println(checkLoShuSquare( twoDAarray ));
}

public static boolean checkLoShuSquare( int[][] twoDAarray ) {
    boolean[] isUnique = new boolean[twoDAarray.length*twoDAarray[0].length+1];
    for ( int i = 0; i < twoDAarray.length; i++ ) {
       for ( int j = 0; j < twoDAarray[0].length; j++ ) {
         if ( isUnique[twoDAarray[i][j]] ){
            return false;
         }
         isUnique[twoDAarray[i][j]] = true;
       }
    }

    int[] lessThan9 = new int[twoDAarray.length*twoDAarray[0].length+1];
    for ( int i = 0; i < twoDAarray.length; i++ ) {
        for ( int j = 0; j < twoDAarray[0].length; j++ ) {
            if (lessThan9[twoDAarray[i][j]] <= 9){
                return true;
            }
    }
  }
    return true;
 }
}

Answer 1

The isUnique array has size 10, instead it should be sized by the largest integer that has been inserted by the user.

Of course, there are better ways to check for duplicate numbers of arbitrary size, like using a Set<Integer> .