Python side in PyJava

This library is designed for Java/Scala invoking python code with Apache Arrow as the exchanging data format. This means if you want to run some python code in Scala/Java, the Scala/Java will start some python workers with this lib's help. Then the Scala/Java will send the data/code to python worker in socket and the python will return the processed data back.

The initial code in this lib is from Apache Spark.