How to print identical matrics and know its is identical matrics

import java.util.*;
public class main{
  public static void main(String args[]){
   Scanner input=new Scanner(System.in);
   int a[][]= {{1,0,0},{0,1,0},{0,0,1}};
		int m=a.length;
		int n=a[0].length;
		
		boolean flag=false;
		for(int i=0;i<m;i++) {
			for(int j=0;j<n;j++) {
				if(i==j&&a[i][j]==1) {
					//System.out.println("true");
					flag=true;
				}
				else {
					//System.out.println("False");
					flag=false;
				}
			}
		}
		
		if(flag==true) {
			System.out.println("true");
		}
		else {
			System.out.println("False");
		}    
  }
}