TechFAQ

Java interview questions

• How to retrieve a key and Value from a map ? view answer
• Why can an interface supertype call methods that belong to Object class? view answer
• Q. What is difference between shallow copy and deep copy ? view answer
• Q.Why to override equals() and hashCode()? and How i can implement both equals() and hashCode() for Set ? view answer
• Q.How to sort list of objects ( User Defined) using comparator? in Descending Order. view answer
• Q. How to sort list of objects ( User Defined) using comparator? view answer
• What is the difference between int and Interger? view answer
• Singleton Double-checked locking in Java? view answer
• What are the parameters to follow Creating and Destroying Objects in Java? view answer
• Q.What are the different scopes for Java variables? view answer
• Q.What method must be implemented by all threads? view answer
• Q.Can an unreachable object become reachable again? view answer
• Q.What are the steps in the JDBC connection? view answer
• Q.How are this() and super() used with constructors? view answer
• Q.What is the difference between static and non-static variables? view answer
• Q.What is the purpose of finalization? view answer
• Q.Does garbage collection guarantee that a program will not run out of memory? view answer
• Q.What is synchronization and why is it important? view answer
• Q.What is daemon thread and which method is used to create the daemon thread? view answer
• Q.What are synchronized methods and synchronized statements? view answer
• Q.If I write System.exit (0); at the end of the try block, will the finally block still execute? view answer
• Q.If I write return at the end of the try block, will the finally block still execute? view answer
• Q.Is it necessary that each try block must be followed by a catch block? view answer
• Q.What is the basic difference between the 2 approaches to exception handling. 1> try catch block and 2> specifying the candidate exceptions in the throws clause? When should you use which approach? view answer
• Q.What are the different ways to handle exceptions? view answer
• Q.What is the difference between error and an exception? view answer
• Q: What is wrapper class? Explain with example? view answer
• Q.What is serialization? Explain with example? view answer
• Q.What one should take care of while serializing the object? view answer
• Q. When you serialize an object, what happens to the object references included in the object? view answer
• Q.What happens to the static fields of a class during serialization? view answer
• Q. Objects are passed by value or by reference? view answer
• Q. Primitive data types are passed by reference or pass by value? view answer
• Q. What type of parameter passing does Java support? view answer
• Q.Can a top level class be private or protected? view answer
• Q.What is the default value of an object reference declared as an instance variable? view answer
• Q.What is the difference between declaring a variable and defining a variable? view answer
• Q. What are different types of inner classes? view answer
• Q. What is Overriding? view answer
• Q.What are Checked and UnChecked Exception? view answer
• Q. What is final? view answer
• Q.What is static in java? view answer
• What is an abstract class? view answer
• Q. What are the modifiers in Java ? view answer
• Q.Difference between HashMap and HashTable? view answer
• Q.Difference between Vector and ArrayList? view answer
• Q.Difference between ArrayList and LinkedList? view answer
• Q.What are pass by reference and passby value in Java? view answer
• Q. When we go for Abstract and Interface in Java? view answer
• Q.What is the difference between interface and abstract class? view answer
• Q.What are the Garbage collection algorithms in Java? view answer
• Q.What is garbage collection and the purpose of garbage collection in Java? view answer
• Q. What is the difference between an Interface and an Abstract class? view answer

!!! Java interview questions !!!

How to retrieve a key and Value from a map ?