what is this?

Answer 1

A reference pointing to the current object of the class.

Answer 2

A neat App filled with examples of Java snippets of code to learn and test on.

Answer 3

Reference holder of current program

Answer 4

reference holder of previous app

Answer 5

this is an app to learn Java and join Java community and "this" is a keyword to represent currently running instance/object.
Be more specific next time onwards.