Java is largely irrelevant to Arduino programming. Running Java needs a JVM (Java Virtual Machine), which is, roughly speaking, a combination of an interpreter and a just-in-time compiler for the JVM bytecode language. This needs quite a bit of memory and computing power. I don't know much about that newer ARM-based Arduino, but my guess is that even that doesn't have nearly enough memory and power to run a JVM.
For Arduino programming, the main languages are C and C++ (or rather, a certain subset of C++).