Does there exist a tool for combining java files
<p>I am joining a competition that requires me to put all my java classes in one single .java file. Does there exist a tool that does this for me (including changing the visibility of classes to be able to do this)?</p>

<p><strong>Addition</strong>: thanks for trying to help me to read the site of the competition but I quote:</p>

<blockquote>
  <p>It is possible to make more than one
  class for your program, but you will
  have to put the source for all classes
  in a single .java file (the compiler
  will produce multiple .class files
  anyway). When you do this, you should
  not declare your classes public, or
  the compiler will complain about it.</p>
</blockquote>

<p>So, only 1 .java file is allowed (no jar) and in that file I can have multiple non-public classes besides my public main class (and not only static inner classes as suggested).</p>
