title: Any risk using a single dollar sign `$` as a java class name?
body: <p>Originally I was using the underscore <code>_</code> as a class name. The new Java8 compiler complains that it "<em>might not be supported after Java SE 8</em>". I changed that to <code>$</code>, and there is no warning any more. However I remember that <code>$</code> is used by Java to indicate an inner/embedded class in the byte code. I am wondering if there is any risk to use a dollar sign <code>$</code> as a class name</p>
  
  <p>Some background to this question. What I want to do is to overcome the fact that Java doesn't support pure function, and the _ or $ is to put an namespace to encapsulate some very generic concept (classes/static methods). and neither do I have a good name for this, nor do I want the lib user type too many things to reference that namespace. Here is the code showing what I am doing under the way: <a href="https://github.com/greenlaw110/java-tool/blob/master/src/main/java/org/osgl/_.java">https://github.com/greenlaw110/java-tool/blob/master/src/main/java/org/osgl/_.java</a></p>