JavaBeat

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 [...]

JDK (Java Development Kit) Java Developer Kit contains tools needed to develop the Java programs, and JRE to run the programs. The tools include compiler (javac.exe), Java application launcher (java.exe), Appletviewer, etc… Compiler converts java code into byte code. Java application launcher opens a JRE, loads the class, and invokes its main method. You need [...]

We recently wrote about watching a directory using the new APIs introduced as part of Java 7. In this post let me throw some light on another class added to the java.nio package as part of Java 7 update- java.nio.file.Files. Another piece of information related to this is that complete java.nio.file package was added as [...]

As a first step into learning Scala and as one who is familiar with Java, let us compare the customary Helloworld programs in Java and Scala. You might already know that to run a Java program, there must be a public class with a main method that takes one parameter, a String[], and has a void return [...]

In Java 7 there were quite a lot of new things added to the File NIO package (java.nio)- there was a new java.nio.file package and java.nio.file.attribute package. Main highlights of the java.nio.file package are the following classes: Path: Its an object used to locate a file or directory in the file system. The value contained [...]

In our previous post we went through the basics of Fork-Join Framework introduced as part of Java 7. In this post lets apply the same Fork-Join to implement Merge sort algorithm. The pseudo code for Merge sort can be found here. In summary the Merge sort algorithm: 1. Divides the array into 1 parts 2. [...]