What is the standard when coding in Java, when do you use camel case when do you use underscores etc.
You stick with the Java Code Conventions.
What exactly the standard is doesn't matter - what matters is that everyone follows it, and you should too.
ClassName
methodName
instanceVariable / localVariable
CONSTANT_NAME
G (Generic Type Parameter)
See Sun's Code Conventions for the Java(TM) Programming Language.