Core Java
In this we will see what is Externalizable Interface and how it is different from Serializable Interface. And also see the program for better understanding.
For interview purpose difference between Hashmap and ConcurrentHashMap is very important. So in this we will see the differences between these two.
A Singleton class in Java is a class that allows only one instance of itself to be created and provides a global point of access to that instance
Difference between interface and abstract class in java. When to use Interface and when to use Abstract class. These two questions are very important for the interview of freshers as well as for experienced candidate.