Academic Tutorials



English | French | Portugese | German | Italian
Home Advertise Payments Recommended Websites Interview Questions FAQs
News Source Codes E-Books Downloads Jobs Web Hosting
Chats

Java Tutorial
Java Introduction
Object Oriented Programming Concepts
Anatomy of a Java Application
Syntax and Semantics of Java
Java Objects, Classes, and Interfaces
The String and StringBuffer Classes in Java
Setting Program Attributes in Java
Using System Resources in Java
Threads of Control in Java
Errors and Exceptions in Java
Java Input and Output Streams
Overview of Java Applet
Creating an Applet User Interface in Java
Communicating with Other Programs in Java
Overview of the Java UI
Using GUI Building Blocks in Java
Laying Out Components within a Container
Working with Graphics in Java
How Java Differs from C and C++
Java Summary

HTML Tutorials
HTML Tutorial
XHTML Tutorial
CSS Tutorial
TCP/IP Tutorial
CSS 1.0
CSS 2.0
HLML
XML Tutorials
XML Tutorial
XSL Tutorial
XSLT Tutorial
DTD Tutorial
Schema Tutorial
XForms Tutorial
XSL-FO Tutorial
XML DOM Tutorial
XLink Tutorial
XQuery Tutorial
XPath Tutorial
XPointer Tutorial
RDF Tutorial
SOAP Tutorial
WSDL Tutorial
RSS Tutorial
WAP Tutorial
Web Services Tutorial
Browser Scripting
JavaScript Tutorial
VBScript Tutorial
DHTML Tutorial
HTML DOM Tutorial
WMLScript Tutorial
E4X Tutorial
Server Scripting
ASP Tutorial
PERL Tutorial
SQL Tutorial
ADO Tutorial
CVS
Python
Apple Script
PL/SQL Tutorial
SQL Server
PHP
.NET (dotnet)
Microsoft.Net
ASP.Net
.Net Mobile
C# : C Sharp
ADO.NET
VB.NET
VC++
Multimedia
SVG Tutorial
Flash Tutorial
Media Tutorial
SMIL Tutorial
Photoshop Tutorial
Gimp Tutorial
Matlab
Gnuplot Programming
GIF Animation Tutorial
Scientific Visualization Tutorial
Graphics
Web Building
Web Browsers
Web Hosting
W3C Tutorial
Web Building
Web Quality
Web Semantic
Web Careers
Weblogic Tutorial
SEO
Web Site Hosting
Domain Name
Java Tutorials
Java Tutorial
JSP Tutorial
Servlets Tutorial
Struts Tutorial
EJB Tutorial
JMS Tutorial
JMX Tutorial
Eclipse
J2ME
JBOSS
Programming Langauges
C Tutorial
C++ Tutorial
Visual Basic Tutorial
Data Structures Using C
Cobol
Assembly Language
Mainframe
Forth Programming
Lisp Programming
Pascal
Delphi
Fortran
OOPs
Data Warehousing
CGI Programming
Emacs Tutorial
Gnome
ILU
Soft Skills
Communication Skills
Time Management
Project Management
Team Work
Leadership Skills
Corporate Communication
Negotiation Skills
Database Tutorials
Oracle
MySQL
Operating System
BSD
Symbian
Unix
Internet
IP-Masquerading
IPC
MIDI
Software Testing
Testing
Firewalls
SAP Module
ERP
ABAP
Business Warehousing
SAP Basis
Material Management
Sales & Distribution
Human Resource
Netweaver
Customer Relationship Management
Production and Planning
Networking Programming
Corba Tutorial
Networking Tutorial
Microsoft Office
Microsoft Word
Microsoft Outlook
Microsoft PowerPoint
Microsoft Publisher
Microsoft Excel
Microsoft Front Page
Microsoft InfoPath
Microsoft Access
Accounting
Financial Accounting
Managerial Accounting
Network Sites


The String and StringBuffer Classes in Java


Previoushome Next





This chapter illustrates different features of String and StringBuffer classes: modifying a StringBuffer,

A D V E R T I S E M E N T
creating Strings and StringBuffers,converting one type of string to another and using of accessor methods to get information about a String or StringBuffer.




The two String Classes

Java programming environment provides two classes which stores and manipulates character data suich as String, for immutable strings (which should not be modified), and StringBuffer for mutable strings (which needs to be modified).

class ReverseString
{
public static String reverseIt(String source)
{
int i, len = source.length();
StringBuffer dest = new StringBuffer(len);

for (i = (len - 1); i >= 0; i--)
{
dest.append(source.charAt(i));
}
return dest.toString();
}
}

The String class is provided for the constant strings; you can use Strings when you don't want its value to be changed. Let us consider for example, if you pass the string data into the method, and you don't want to modify the string by the method in any way, you can use "String". Typically, Strings are used to pass character data to methods and return character data from the methods. method reverseIt() takes an String argument and returns back a String value.

A StringBuffer class is used for non-constant string. When we know that value of the character data will do change we use StringBuffers. Typically StringBuffers are used for constructing the character data like that of reverseIt() method.




Creating Strings and StringBuffers classes

The reverseIt method in the above example creates a StringBuffer called "dest" whose initial length is equal to that of source. StringBuffer dest declares to the compiler that dest will be used to refer to an object whose type is of String, the new operator will allocate memory for the new object, and StringBuffer() will initialize the object. When we create any object in a Java program, we always do use the same three steps: declaration, instantiation, initialization.




The Accessor Methods

Methods which are used to obtain information about the object are known as accessor methods. The method reverseIt() uses two String's accessor methods to get the information about a source string.

First, reverseIt() uses String's length()
accessor method to obtain the length of the String source.
int len = source.length();

Second, reverseIt() uses the charAt()
accessor which returns the character at the position specified in the parameter.
source.charAt(i)




Modifying a StringBuffer

To add characters to dest reverseIt() method uses StringBuffer's append() method. In addition to append() method, StringBuffer also provides methods to insert characters into buffer or modify the character at a specific location within buffer, among others.

dest.append(source.charAt(i));

append() is the only StringBuffer's methods which allows you to append data to end of the StringBuffer. There are different append() methods which appends data of various types, like boolean, float, int, and even Object, to the end of the StringBuffer. The data is first converted into string before the append could takes place.




Converting the Objects to Strings

toString() Method
Sometimes it becomes necessary to convert an object into String because you may need to pass it to a method that accepts only String values. consider for example, System.out.println() will not accept StringBuffer, so there is need to convert a StringBuffer to String before you could print it. The reverseIt() method in the above example uses StringBuffer's toString() method to converte StringBuffer into String object before returning the String.

return dest.toString();

many of the classes in java.lang supports toString() including all the "type wrapper" classes such as Integer, Boolean,Character and others. Even the base Object class has toString() method which converts an Object to String. When we write a subclass of an Object, we can override the method toString() to perform the more specific conversion for the subclass.

valueOf() Method
for convenience, the String class do provides the static method "valueOf()" which we can use to convert variables of different types to the String. For example, to print the value of the pi

System.out.println(String.valueOf(Math.PI));



Be the first one to comment on this page.




  Java Tutorial eBooks
More Links » »
 
 Java Tutorial FAQs
More Links » »
 
 Java Tutorial Interview Questions
More Links » »
 
 Java Tutorial Articles
More Links » »
 
 Java Tutorial News
More Links » »
 
 Java Tutorial Jobs
More Links » »

Share And Enjoy:These icons link to social bookmarking sites where readers can share and discover new web pages.
  • blinkbits
  • BlinkList
  • blogmarks
  • co.mments
  • connotea
  • del.icio.us
  • De.lirio.us
  • digg
  • Fark
  • feedmelinks
  • Furl
  • LinkaGoGo
  • Ma.gnolia
  • NewsVine
  • Netvouz
  • RawSugar
  • Reddit
  • scuttle
  • Shadows
  • Simpy
  • Smarking
  • Spurl
  • TailRank
  • Wists
  • YahooMyWeb

Previoushome Next

Keywords: java stringbuffer, stringbuffer reverse, stringbuffer append, string str

HTML Quizzes
HTML Quiz
XHTML Quiz
CSS Quiz
TCP/IP Quiz
CSS 1.0 Quiz
CSS 2.0 Quiz
HLML Quiz
XML Quizzes
XML Quiz
XSL Quiz
XSLT Quiz
DTD Quiz
Schema Quiz
XForms Quiz
XSL-FO Quiz
XML DOM Quiz
XLink Quiz
XQuery Quiz
XPath Quiz
XPointer Quiz
RDF Quiz
SOAP Quiz
WSDL Quiz
RSS Quiz
WAP Quiz
Web Services Quiz
Browser Scripting Quizzes
JavaScript Quiz
VBScript Quiz
DHTML Quiz
HTML DOM Quiz
WMLScript Quiz
E4X Quiz
Server Scripting Quizzes
ASP Quiz
PERL Quiz
SQL Quiz
ADO Quiz
CVS Quiz
Python Quiz
Apple Script Quiz
PL/SQL Quiz
SQL Server Quiz
PHP Quiz
.NET (dotnet) Quizzes
Microsoft.Net Quiz
ASP.Net Quiz
.Net Mobile Quiz
C# : C Sharp Quiz
ADO.NET Quiz
VB.NET Quiz
VC++ Quiz
Multimedia Quizzes
SVG Quiz
Flash Quiz
Media Quiz
SMIL Quiz
Photoshop Quiz
Gimp Quiz
Matlab Quiz
Gnuplot Programming Quiz
GIF Animation Quiz
Scientific Visualization Quiz
Graphics Quiz
Web Building Quizzes
Web Browsers Quiz
Web Hosting Quiz
W3C Quiz
Web Building Quiz
Web Quality Quiz
Web Semantic Quiz
Web Careers Quiz
Weblogic Quiz
SEO Quiz
Web Site Hosting Quiz
Domain Name Quiz
Java Quizzes
Java Quiz
JSP Quiz
Servlets Quiz
Struts Quiz
EJB Quiz
JMS Quiz
JMX Quiz
Eclipse Quiz
J2ME Quiz
JBOSS Quiz
Programming Langauges Quizzes
C Quiz
C++ Quiz
Visual Basic Quiz
Data Structures Using C Quiz
Cobol Quiz
Assembly Language Quiz
Mainframe Quiz
Forth Programming Quiz
Lisp Programming Quiz
Pascal Quiz
Delphi Quiz
Fortran Quiz
OOPs Quiz
Data Warehousing Quiz
CGI Programming Quiz
Emacs Quiz
Gnome Quiz
ILU Quiz
Soft Skills Quizzes
Communication Skills Quiz
Time Management Quiz
Project Management Quiz
Team Work Quiz
Leadership Skills Quiz
Corporate Communication Quiz
Negotiation Skills Quiz
Database Quizzes
Oracle Quiz
MySQL Quiz
Operating System Quizzes
BSD Quiz
Symbian Quiz
Unix Quiz
Internet Quiz
IP-Masquerading Quiz
IPC Quiz
MIDI Quiz
Software Testing Quizzes
Testing Quiz
Firewalls Quiz
SAP Module Quizzes
ERP Quiz
ABAP Quiz
Business Warehousing Quiz
SAP Basis Quiz
Material Management Quiz
Sales & Distribution Quiz
Human Resource Quiz
Netweaver Quiz
Customer Relationship Management Quiz
Production and Planning Quiz
Networking Programming Quizzes
Corba Quiz
Networking Quiz
Microsoft Office Quizzes
Microsoft Word Quiz
Microsoft Outlook Quiz
Microsoft PowerPoint Quiz
Microsoft Publisher Quiz
Microsoft Excel Quiz
Microsoft Front Page Quiz
Microsoft InfoPath Quiz
Microsoft Access Quiz
Accounting Quizzes
Financial Accounting Quiz
Managerial Accounting Quiz
Testimonials | Contact Us | Link to Us | Site Map
Copyright © 2008. Academic Tutorials.com. All rights reserved Privacy Policies | About Us
Our Portals : Academic Tutorials | Best eBooksworld | Beyond Stats | City Details | Interview Questions | Discussions World | Excellent Mobiles | Free Bangalore | Give Me The Code | Gog Logo | Indian Free Ads | Jobs Assist | New Interview Questions | One Stop FAQs | One Stop GATE | One Stop GRE | One Stop IAS | One Stop MBA | One Stop SAP | One Stop Testing | Webhosting in India | Dedicated Server in India | Sirf Dosti | Source Codes World | Tasty Food | Tech Archive | Testing Interview Questions | Tests World | The Galz | Top Masala | Vyom | Vyom eBooks | Vyom International | Vyom Links | Vyoms | Vyom World
Copyright © 2003-2017 Vyom Technosoft Pvt. Ltd., All Rights Reserved.