title: Create a mutable java.lang.String
body: <p>It's common knowledge that Java <code>String</code>s are immutable. Immutable Strings are great addition to java since its inception. Immutability allows fast access and a lot of optimizations, significantly less error-prone compared to C-style strings, and helps enforce the security model.</p>
  
  <p>It's possible to create a mutable one without using hacks, namely</p>
  
  <ul>
  <li><code>java.lang.reflect</code></li>
  <li><code>sun.misc.Unsafe</code></li>
  <li>Classes in bootstrap classloader</li>
  <li>JNI (or JNA as it requires JNI)</li>
  </ul>
  
  <p>But is it possible in just plain Java, so that the string can be modified at any time? The question is <em>How</em>?</p>