title: sort 2D array based on two columns
body: <p>I have 2D array and it has 2 columns and I want to sort this.</p>
  
  <hr>
  
  <p>input is this:</p>
  
  <p>first column..... second column</p>
  
  <p>3......................2</p>
  
  <p>4......................9</p>
  
  <p>3......................1</p>
  
  <p>5......................0</p>
  
  <p>1......................2</p>
  
  <hr>
  
  <p>output is this:</p>
  
  <p>first column..... second column</p>
  
  <p>5......................0</p>
  
  <p>4......................9</p>
  
  <p>3......................2</p>
  
  <p>3......................1</p>
  
  <p>1......................2</p>
  
  <hr>
  
  <p>I beginner in Java.</p>
  
  <p>please help me whit a code of function(mySort(int[][] arr) to sort the array.</p>