title: Operators in java: '+' with '=' vs '+='
body: <p>I often use both forms: short and long of addition (also subtraction, multiplication, etc.) operator in java. And I thought that this doesn't impact to performance or speed, but I was confused by questions: "Why java creators provided two forms of this operators? And what is the difference between them?" So, what's real difference between two forms:</p>
  
  <pre><code>int a = 10, b = 3;
  b = b + a;
  </code></pre>
  
  <p>and </p>
  
  <pre><code>int a = 10, b = 3;
  b += a;
  </code></pre>
  
  <p>Can someone explain me this? May be difference between two forms is hidden at a lower level?
  Every book says only: "Java also has compound operators..." but nothing about difference.</p>