Very often used many StringBuffer Methods are discussed with Examples and Screenshots in Simple terms for a Beginner. StringBuffer Methods for Searching characters The indexOf(), lastIndexOf() and charAt() methods existing in String class also exist in StringBuffer class. They can be used with StringBuffer object. The meaning of the methods is just same of String …
StringBuffer substring Java Pass By Reference Many petty methods exist with StringBuffer like substring(), setLength() and trimToSize() etc. These methods are not much used in regular programming. public class MiscellaneousMethods { public static void main(String args[]) { // using substring(), to extract part of a string StringBuffer buffer1 = new StringBuffer(“TajMahal”); String s1 = buffer1.substring(3); …
Hierarchy of Exceptions (Checked Unchecked Exceptions) After knowing exceptions and exception handling mechanism, let us explore how many exceptions exist, are they inheriting from a common super class, any classification exists or not etc. Whenever you come across a new Java class, it is essential to know its super classes, so that, you can use …
Hierarchy Exceptions Checked Unchecked Exceptions Read More »
We know earlier, Java does not support multiple inheritance, basically. But to support multiple inheritance, partially, Java introduced "interfaces". An interface is not altogether a new one for us; just it is a special flavor of abstract class where all methods are abstract. That is, an interface contains only abstract methods. Syntax of multiple inheritance …
Exception Handling try catch Summary: "Exception Handling try catch" shows the importance of handling exceptions in Java. Let us write one example of code, to see the weakness and robustness of exception handling. 1. Exception Unhandled The following program explains the drawback of not handling the exception. public class ExceptionNotBothered { public static void main(String …
Runtime Error Groups Exception causes Summary: In this "Runtime Error Groups Exception causes" tutorial, you will come to know the classification of excetpions and causes in detail. Runtime Error – Groups We know earlier, the runtime errors cause the unwarranted termination of the execution of a smooth running process. The runtime errors can be broadly …
We know earlier, in method overriding, the subclass method supersedes the super class method. When the method is overridden in inheritance, the subclass object calls its own method. If it calls its own method, the subclass looses the functionality of the super class method (of course, subclass is at liberty). If the subclass would like …
A constructor looks more like a method but without return type. Moreover, the name of the constructor and the class name should be the same. The advantage of constructors over methods is that they are called implicitly whenever an object is created. In case of methods, they must be called explicitly. To create an object, …
Observer Observable Introduction Sometimes, it may be necessary to get notified when the data changes in a data structure. To accomplish this job, the Java designers introduced Observer and Observable classes with JDK 1.0, the starting version itself. Observer is an interface and Observable is a class, both from java.util package. As the names are …
Example on Moving Banner and Applet cum Application that works applet as an application also Banner is a string that moves either horizontally or vertically across the applet window. In the following program, the string "S N Rao" is moved horizontally. This is done both as applet and application ( Applet cum Application ). Before …
Applet Example: Drawing Strings and Graphics in Applets given with Screenshots in Simple terms for a Beginner. After practicing the earlier simple life cycle program, let us write another program that prints some strings on applet window (not at DOS prompt as done previously). Now we use the java.awt.Graphics object passed as parameter to paint() …
class Calendar TimeZone Locale Summary: After reading this "class Calendar TimeZone Locale" you will come to know the usage of the methods of Date and Calendar class. Also learn to print the date as per timezone or country. Introduction Date and Calendar We know many methods of Date class are deprecated; observe the screenshot of …
After knowing the data structures from java.util package, let us discuss about the remaining classes of java.util package. The classes include Date and GregorianCalendar to manipulate dates, Random class to generate random numbers and StringTokenizer to separate the string into individual words (known as tokens). The other classes less used are Observer, Observable, Timer and …
Shallow Copying Vs Deep Copying: Copying an object involves getting another object with the same properties of the original. Here, there exists two ways – two objects having their own set of properties (instance variables) or both objects referring the same location of properties. Following gives the detailed discussion. Shallow Copying Shallow copying is the …
Shallow Copying Vs Deep Copying Copying an Object Read More »
Introduction to Inner classes Java JDK 1.1 introduced a new type of classes known as inner classes. All the classes you have done so far are known as top-level classes. A class written inside another class is known as "inner class" or "nested class". That is, an inner class is enclosed within another class. Inner …
Garbage Collection gc() exit(0) Summary: In this "Garbage Collection gc() exit(0)", the basics of garbage collection focusing the methods gc() and exit(0) illustrated. More on Garbage Collection gc() exit(0) methods Unwanted (not used in the remaining part of the program) objects generated in the process are known as garbage. Java includes a special built-in style …
About finalize() Java Destructor method The finalize() method is equivalent to a destructor of C++. When the job of an object is over, or to say, the object is no more used in the program, the object is known as garbage. The process of removing the object from a running program is known as garbage …
UDP Protocol Example Summary: All the earlier programs are based on TCP/IP protocol. Here "UDP Protocol Example" discusses the basics of UDP protocol. Later postings gets you the programs. User Datagram Protocol (UDP) It is advised to go through the network and socket basics before proceeding to the UDP protocol. UDP stands for User Datagram …
Java is very strong in communication world. To support, LAN programming, the java.net package comes with two classes Socket and ServerSocket. The meaning and purpose these classes and network related basics, you have studied in Networking – Introduction. Socket and ServerSocket are extensively I/O streams for data traversal and for this reason, sockets are called …
URLConnection URL Summary: In this "URLConnection URL", you will know how to read a file with URLConnection class. Methods of classes URLConnection and URL are explained with example code, explanation and screenshots. Are You Busy – A program on ServerSocket The developer can easily know which port number on the server is busy so that …