Java's implementation is now managed via the OpenJDK. If you want to [contribute][1], you'll need to follow this path, summarized from the page linked:

 1. Find something to work on. You seem to have this step complete.
 
 2. Discuss your intended change(s) with others on the project

 3. Submit a patch. You'll need to know how to use [Mercurial][2] and how to do [unit testing][3] in order to complete this step.

 4. You'll then need to get a sponsor who is already working as a JDK 8 update or JDK 9 committer. They'll evaluate your work and work with you to address deficiencies. 

 5. Your code gets incorporated into the JDK. Or not, mostly likely not. They recommend making sure that you really know what you are doing before you start working on this kind of a project. They also recommend hacking against the JDK 9 sources before you try to start submitting features.

All told what you ask is doable but *very* difficult. A better option might be to devise a library or framework that houses your classes and then put it up on Github or Bitbucket and try to attract interest in usage and improvement.

  [1]: http://openjdk.java.net/contribute/
  [2]: http://hginit.com/
  [3]: http://openjdk.java.net/jtreg/