title: How to convert hex strings to byte values in Java
body: <p>I have a String array.
  I want to convert it to byte array.
  I use the Java program.
  For example:</p>
  
  <pre><code>String str[] = {"aa", "55"};
  </code></pre>
  
  <p>convert to:</p>
  
  <pre><code>byte new[] = {(byte)0xaa, (byte)0x55};
  </code></pre>
  
  <p>What can I do?</p>