 <p>String supports only <code>+</code> and <code>+=</code>. All other arithmetic and compound statements are invalid at compile time itself. </p> <p>From <a href="http://docs.oracle.com/javase/7/docs/api/java/lang/String.html" rel="nofollow"><code>String docs</code></a> </p> <blockquote> <p>The Java language provides special support for the string concatenation operator ( + ), and for conversion of other objects to strings.</p> </blockquote> <p>That doesn't mean it support all other operations.</p> <p>To substract or to make parts of string, there are other methods like <code>substring</code>, <code>split</code> etc.</p> <p>Here are some examples to substring, from docs </p> <pre><code> String c = "abc".substring(2,3); </code></pre>