title: Java question about autoboxing and object equality / identity
body: <pre><code>public class Main { 
      /** 
        * @param args the command line arguments */ 
      public static void main(String[] args) { 
          // TODO code application logic here
          int a1 = 1000, a2 = 1000; 
          System.out.println(a1==a2);//=&gt;true 
          Integer b1 = 1000, b2 = 1000;
          System.out.println(b1 == b2);//=&gt;false 
          Integer c1 = 100, c2 = 100; 
          System.out.println(c1 == c2);//=&gt;true 
      }
  
  }
  </code></pre>
  
  <p>Why is <code>b1 == b2</code> false and <code>c1 == c2</code> true?</p>