JSNI is a web equivalent of inline assembly code and can use in many ways such as :
* Implement a Java method directly in JavaScript.
* Wrap type-safe Java method signatures around existing JavaScript.
* Call from JavaScript code into Java code and vice-versa.
* Throw exceptions across Java/JavaScript boundaries.
* Read and write Java fields from JavaScript.
* Use development mode to debug both Java source (with a Java debugger) and JavaScript (with a script debugger).
