1. questions on Multithreading - how to spawn all the threads at the same time how to start the thread from different classes, how would you create 100 threads? 2. Questions on Collections - the difference between list and set, unordered vs ordered map, which map offers insertion order? , calculate the size of the set and list on the custom question they asked 3. Exception Handling - parents class of Exception, Compile time exception vs Runtime Exception, IO exception questions related to File, custom exception, use of throw keyword, an example of compile-time exceptions 4- OOPs concept - Encapsulation, inheritance, polymorphism, ask me to show examples of method overriding, few basic depth questions on method overriding if the static method can be overloaded, what is method shadowing? where is the equals method is defined in Java?