[IJava] A Jupyter kernel for executing Java code

As we know that Jupyter’s is a Python-based solution, and it provides a lot of convenience for interactivity with Python code. But, I just wonder if Jupyter can use Java as its kernel, and it can. I find that it allows to integrate additional "kernels" with Java capabilities and someone has done it -IJava: https://github.com/SpencerPark/IJava

Google Web Toolkit

If you are familiar with Java programming but not familiar Ajax (Asynchronous JavaScript + XML) , Google Web Toolkit (GWT) is a good choice to deal with Ajax web application.
GWT provides its APIs for developers to write Java code in the program, and then compiles to JavaScript. In the web site of GWT, it gives a lot of features about GWT, and explains how to translate Java code to JavaScript.
Some people may have an question why I need to write Java code instead of JavaScript directly? In my opinion, it is about "software engineering". It may be easy if you only have a small or not so big Ajax application. Once you have more and more projects that need to do, you probably will find that your debugging time is longer than you think and your source code is hard to be reused. Due to these issues above, Google develops this way to deal with Ajax. Using GWT, we can leverage Java's ability and Java IDE tool to build application logic through well-designed object-oriented techniques.