[ZEPPELIN-2020] Invoke method from resource

[Leemoonsoo]

What is this PR for?

This PR provides a way to invoke method remotely against the resource in the resource pool.
This will be particularly useful when the object in the resource pool is non-serializable (like jdbc connection, spark dataframe).

This PR extends data access API of Resource from

class Resource {
  // get object
  public Object get();
}

to

class Resource {
  // get object
  public Object get()

  // call method of object and get return value
  public Object invokeMethod(String methodName, Class [] paramTypes, Object [] params);

  // call method of object and save return value into resourcepool
  public Resource invokeMethod(String methodName, Class [] paramTypes, Object [] params, String returnResourceName);
}

What type of PR is it?

Feature

Todos

• - API for remote method invocation and get result
• - API for remote method invocation and store result into resource pool
• - Unittest

What is the Jira issue?

https://issues.apache.org/jira/browse/ZEPPELIN-2020

How should this be tested?

Unittest included

Questions:

• Does the licenses files need update? no
• Is there breaking changes for older versions? no
• Does this needs documentation? no

[felixcheung]

should it fail / exit then without passing o along? Since o can be null in that case

[Leemoonsoo]

Still need to put null into getInvokeResponse, otherwise, https://github.com/apache/zeppelin/pull/1951/files#diff-5d91426e574ad85664eb7a7857ef6e90R207 may not finish.

[Leemoonsoo]

Merge to master if no further discussions