Where is this used? This is used to analyze/modify the behaviour of a class at runtime. Using this, you can view or change the private/public fields at wish (without exposing any getter/setter). Personally, I have used this in one of our projects at GreyOrange to write unit test cases. Using this in main code is a big no-no as it exposed you critical fields to the world.
Main Class Let’s create a main class for which we will write some test cases.