core java in java questions asked in companies

It is very useful to have strings implemented as final or immutable objects. Below are some advantages of String Immutability in Java Immutable objects are thread-safe. Two threads can both work on an immutable object at the same time without any possibility of conflict. Security: the system can pass on sensitive bits of read-only information … Read more

The main difference between the three most commonly used String classes as follows. StringBuffer and StringBuilder objects are mutable whereas String class objects are immutable. StringBuffer class implementation is synchronized while StringBuilder class is not synchronized. Concatenation operator “+” is internally implemented by Java using either StringBuffer or StringBuilder. Criteria to choose among String, StringBuffer … Read more

  To create a object immutable You need to make the class final and all its member final so that once objects gets crated no one can modify its state. You can achieve same functionality by making member as non final but private and not modifying them except in constructor. Also its NOT necessary to … Read more

A Java object is considered immutable when its state cannot change after it is created. Use of immutable objects is widely accepted as a sound strategy for creating simple, reliable code. Immutable objects are particularly useful in concurrent applications. Since they cannot change state, they cannot be corrupted by thread interference or observed in an … Read more

In one of our old JAVA projects we had an inheritance depth of five. Believe us we never liked that code. It’s bad to have a huge inheritance depth. A maintainable inheritance depth should be maximum 5. Anything above that is horrible. There is no limit as such specified anywhere that there is some limit … Read more