A comparator interface is used to buy the objects of consumer-described lessons. A comparator item is effective at evaluating two objects of a similar course. Adhering to perform compare obj1 with obj2. Evaluating null objects may well cause unpleasant NullPointerException though functioning your code, something you want to avoid. Observe: https://lambda-with-comparators88654.designertoblog.com/42199856/fascination-about-java-8-lambda-stream-sorted