In this article I shall discuss about how to compress files using Java. Java has a package of classes that allow data compression.Let’s see how easy it is to compress all files in a folder.The first step is to import the classes that we will use: Working with java.util.zip files Package java.io classes will be […]

When you need some sort of ordering for the classes which you define, you will be going either for a comparable or comparator interface. Consider this example package test; import java.util.*; public class TreeSetTest { private static Set<Person> s = new TreeSet<Person>(); public static void main(String a[]){ s.add(new Person(20)); s.add(new Person(30)); s.add(new Person(10)); s.add(new Person(50)); […]

keyword : this ‘this’ is used for pointing the current class instance. It can be used with variables or methods. Look into the following example: class Test{ private int i=10; public void m(){ System.out.println(this.i); } } In the above code this is used for the current instance. Since this is instance of a class it […]

They are called shift operators and they operate by shifting the number of bits being specified as an operand in the operation. >> —> Right shift Operator << —> Left Shift Operator >>> —-> Right bit with zero fill operator. The first two maintain the MSB when shifting thereby they maintain the sign of the […]

Explanation : 1 They both differ very much in their significance. equals() method is present in the java.lang.Object class and it is expected to check for the equivalence of the state of objects! That means, the contents of the objects. Whereas the ‘==’ operator is expected to check the actual object instances are same or […]

List is an interface and ArrayList is an implementation of the List interface. The arraylist class has only a few methods in addition to the methods available in the List interface. There is not much difference in this. The only difference is, you are creating a reference of the parent interface in the first one […]