PayPal Software QA Engineer interview questions

A software engineer comes up with "google searched" coding question for which I am sure he did not know the answer because when I asked him whats the exact solution since got to the closest possible in that 5 minutes of thinking, he did not give me the solution he looked lost himself! He wrote something on the board but when I walked through a sample scenario it did not work. So when he as a interviewer after research did not have a "perfect" answer, he expects me to solve in that 3 - 5 mins?! Now I wait and wait for weeks after they spoke to me the salary expectations etc and then they say btw they want to do another round of interview. Forget it!!!

Is Integer a Class or variable where can static keyword used ? Adv and Disadv of using Static variable what are things need to keep in mind when using static variable how can we apply locks static variable or how can we make sure static variable is not tamper with Java Complier and JVM - which on start first Abstract vs Interface why we need interface when abstract can do same stuff for us Can you use Interface.method?