A single element in the Vector can be removed using the java.util.Vector.remove() method. This method removes the element at the specified index in the Vector. It returns the element that was removed. Also after the element is removed from the specified index, the rest of the Vector elements are shifted ... Read More

The factorial of any non-negative integer is basically the product of all the integers that are smaller than or equal to it. The factorial can be obtained using a recursive method.A program that demonstrates this is given as follows:Example Live Demopublic class Demo {    public static long fact(long n) { ... Read More

All the elements of a vector can be replaced by a specific element using java.util.Collections.fill() method. This method requires two parameters i.e. the Vector and the element that replaces all the elements in the Vector. No value is returned by the Collections.fill() method.A program that demonstrates this is given as ... Read More

The data members and methods of a class can be accessed from the same package or sub-classes in a different package if they are specified with the protected access modifier. The keyword protected is used to specify this modifier.A program that demonstrates the protected access modifier in Java is given ... Read More

A class is an abstract class if it contains at least one abstract method. It can contain other non-abstract methods as well. A class can be declared as abstract by using the abstract keyword. Also, an abstract class cannot be instantiated.A program that demonstrates an abstract class in Java is ... Read More

A list can be sorted in reverse order i.e. descending order using the java.util.Collections.sort() method. This method requires two parameters i.e. the list to be sorted and the Collections.reverseOrder() that reverses the order of an element collection using a Comparator.The ClassCastException is thrown by the Collections.sort() method if there are ... Read More

To send an e-mail using your Java Application is simple enough but to start with you should have JavaMail API and Java Activation Framework (JAF) installed on your machine. You can download latest version of JavaMail (Version 1.2) from Java's standard website. You can download latest version ... Read More

As we know that Hash map in Java does not maintain insertion order either by key or by order.Also it does not maintain any other order while adding entries to it. Now in order to sort a hash map according to the values mapped to its corresponding keys we first ... Read More

A Singleton pattern states that a class can have a single instance and multiple instances are not permitted to be created. For this purpose, we make the constructor of the class a private and return a instance via a static method. But using cloning, we can still create multiple instance ... Read More

The java.util.PriorityQueue class is an unbounded priority queue based on a priority heap.Following are the important points about PriorityQueue − The elements of the priority queue are ordered according to their natural ordering, or by a Comparator provided at queue construction time, depending on which constructor is used. A ... Read More