Type Casting Converting one data type into another data type is called "Type Casting". Type of Data Types There are two types of data...

Abstract Method and Abstract Class An abstract method does not contain any body.It contains only the method header.So we can say it is...

What is the difference between an abstract class and an interface? Ans: Abstract Class: 1.An abstract class is written when there are...

Multiple Inheritance using Interfaces We know that in multiple inheritance ,sub classes are derived from multiple super classes.If two...

What is an Interface? Ans: An Interface is a specification of method prototypes.All the methods of the interface are public and...

What is the difference between throws and throw? Ans: throws clause is used when the programmer does not want to handle the exception and...

throws Clause Even if the programmer is not handling run-time exceptions,the java compiler will not give any error related to run-time...

Exception Handling When there is an exception ,the user data may be corrupted.This should be tackled by the programmers be carefully...

Exception Handling A software engineer commit many errors while developing software code.These errors are also called Bugs and the...

String Tokenizer Class This class is useful to break a string into pieces called Tokens.These tokens are then stored in the...

Using Comparator to Sort an Array It offers an interface , called Comparator that is useful to impose a total ordering on a collection of...

Array Class Arrays class provides methods to perform certain operations on any one dimensional array.All the methods of the array class...

What is difference between HashMap and Hashtable? Ans: HashMap= HashMap is not synchronized.In case of single thread, using HashMap is...

Hashtable Class Hashtable is similar to HashMap which can store elements in the form of key-value pairs.But Hashtable is synchronized...

Hash Map Class HashMap is a collection that stores elements in the form of key-value pairs.If key is provided,its corresponding value can...

Vector Class A vector also stores elements similar to ArrayList, but Vector is synchronized.It means if several threads act on same...

ArrayList Class An ArrayList is like an array, which can grow in memory dynamically.Memory is dynamically allotted and re-allotted to...

LinkedList Class A Linked list contains a group of elements in the form of nodes.Each node will have three fields---the data field...

LinkedHashSet Class This is a subclass of HashSet class and does not contain any additional members on its own.It is a generic class that...

HashSet Class A HashSet represents a set of elements.it does not guarantee the order of elements.Also it does not allow the duplicate...