Finish the translation for the remaining classes to Java 8 from Groovy

[jdigger]

Per GH-125

This may need to be more of an epic, depending on what is found as we get in there. Converting from Groovy-style collections handling to JDK 8 Streams should be a pretty straight-forward mechanical translation (that IDEA's "to Java" refactoring doesn't do). But to the extent we're using more advanced features like builders this could be more complicated.