zeppelin/java
Vincenzo Selvaggio ac2e957e2d [ZEPPELIN-3653] - New Java interpreter
### What is this PR for?
**New Java interpreter**
There are several Java libraries that could be used to leverage the Data Visualization & Collaboration features of Zeppelin hence the need of a Java interpreter to run any java code / library with no further dependencies.
Dependencies to any java library can be added by the end users in the Java Zeppelin interpreter Dependencies settings section.

### What type of PR is it?
* Feature

### Todos
* Any feedback from reviewers

### What is the Jira issue?
* [ZEPPELIN-3653]

### How should this be tested?
Manually
* Start the Zeppelin server
* Create a new note with the java interpreter binding
* Write some java code as per documentation (docs/interpreter/java.md)
Unit tests
* Run unit tests (JavaInterpreterTest.java and JavaInterpreterUtilsTest.java)

### Screenshots (if appropriate)

### Questions:
* Does the licenses files need update?
No, the dependency on com.thoughtworks.qdox was already added as part of the Beam Interpreter.
* Is there breaking changes for older versions?
No.
* Does this needs documentation?
Yes, it has been added to the PR, see docs/interpreter/java.md.

Author: Vincenzo Selvaggio <vselvaggio@hotmail.it>

Closes #3092 from selvinsource/java-interpreter and squashes the following commits:

c5f96b27d [Vincenzo Selvaggio] Excluding java interpreter from zeppelin-server tests.
3f85f1cd3 [Vincenzo Selvaggio] Removed redundant java profile as result of rebasing.
b68634034 [Vincenzo Selvaggio] Updated documentation for Java interpreter to be more explicit on the limitations.
ce9401079 [Vincenzo Selvaggio] Updated Java Interpreter README and documentation.
9e9a859e9 [Vincenzo Selvaggio] Stylecheck fixes.
706aa0795 [Vincenzo Selvaggio] PR reviews changes: -updated interpreter list -direct import of java module and update related README -static logger for Java interpreter
d2358f5dc [Vincenzo Selvaggio] Updated documentation for Java interpreter by adding relevant examples.
b57f1cfd0 [Vincenzo Selvaggio] Added Java Interpreter Utils and tests for them.
f542a4f61 [Vincenzo Selvaggio] Java Interpreter first version
2018-08-03 09:15:19 +08:00
..
src [ZEPPELIN-3653] - New Java interpreter 2018-08-03 09:15:19 +08:00
pom.xml [ZEPPELIN-3653] - New Java interpreter 2018-08-03 09:15:19 +08:00
README.md [ZEPPELIN-3653] - New Java interpreter 2018-08-03 09:15:19 +08:00

Overview

Java interpreter for Apache Zeppelin

Architecture

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

Technical overview

  • 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.