Add alternate framework instructions to Java documentation

[Rperry2174]

In #169 we realized that there is room for alternate build systems. See this comment here for more detail.

For now we show two, but should add documentation for the others as well:

• Plain Java
• Spring framework
• Vaadin
• Spark
• Grails
• Play
• etc(?)

We can do this via code snippet vairables here as well as tab groups