I have many many adhoc and general utility classes that I have written over the years in various projects. Some of them are wrappers/adapters to other libraries.
For Java its a challenge to share this code because each utility class may have very different dependencies (for example I have some classes that require guava and others commons-lang).
The obvious choice is to github my code and blog about it. Annoyingly I have make a project (Maven pom) for each utility class (not to mention lots of jars).
How do others share utility code (not full blow libraries)?
If they're things you just want to save, but don't want to make a full-blown project out of, try https://gist.github.com. Bonus points if you blog about it too, you can embed the gist directly in your blog post.