title: preincrement / postincrement in java
body: <p>Can someome help me to understand why: </p>
  
  <pre><code>int i=1;
  int j=1;
  int k=1;
  int l=1;
  
  System.out.println(i++ + i++);  
  System.out.println(++j + ++j);  
  System.out.println(k++ + ++k);  
  System.out.println(++l + l++);
  </code></pre>
  
  <p>give:</p>
  
  <p>3<br>
  5<br>
  4<br>
  4  </p>