Java interpreter for Apache Zeppelin

Current interpreter implementation supports the static REPL. It compiles the code in memory, execute it and redirect the output to Zeppelin.

• Upon starting an interpreter, an instance of JavaCompiler is created.

• When the user runs commands with java, the JavaParser go through the code to get a class that contains the main method.

• Then it replaces the class name with random class name to avoid overriding while compilation. It creates new out & err stream to get the data in new stream instead of the console, to redirect output to Zeppelin.

• If there is any error during compilation, it can catch and redirect to Zeppelin.

• JavaInterpreterUtils contains useful methods to print out Java collections and leverage Zeppelin's built in visualization.