Sachin Thapa

Class data sharing (CDS) a feature introduced in J2SE 5.0 reduces the startup time for Java programming language applications. When the JRE is installed on 32-bit platforms using the Sun provided installer, the installer loads a set of classes from the system jar file into a private internal representation, and dumps that representation to a file, called a "shared archive".Class data sharing is not supported in Microsoft Windows 95/98/ME. During subsequent JVM invocations, the shared archive is memory-mapped in, saving the cost of loading those classes and allowing much of the JVM's metadata for these classes to be shared among multiple JVM processes. The primary motivation for including CDS in the 5.0 release is the decrease in startup time it provides. CDS produces better results for smaller applications because it eliminates a fixed cost: that of loading certain core classes. The smaller the application relative to the number of core classes it uses, the larger the sav...

XML is the base of Web 2.0 development. While writing a web service to integrate products, I learned some best practices with XML naming conventions. An XML element is everything from (including) the element's start tag to (including) the element's end tag. An element can contain other elements, simple text or a mixture of both. Elements can also have attributes. <bookstore> <book category="CHILDREN"> <author>J K. Rowling</author> <year>2005</year> <price>29.99</price> </book> <book category="WEB"> <author>Erik T. Ray</author>> <year>2003</year> <price>39.95</price> </book> </bookstore>> In the example above, and have element contents, because they contain other elements. has text content because it contains text. In the example above only has an attribute (category="CHILDREN"). XML Naming Rules XML elements mus...

This article covers details about writing a web service client using Apache AXIS2 API. The article explains the various API using code snippets and covers parameters require by various methods of web service client API. Apache AXIS2 web service API mainly consists of two type of objects ServiceClient and OperationClient. ServiceClient provides basic APIs to send and receive SOAP messages, for advanced methods you require Operation Client. To provide target URL you need to define a EndPointReference type of object. EndpointReference targetEPR = new EndpointReference(http://localhost:8080/axis2/services/helloworld); Various options can be given to web service client by creating an Options object. The reference point defined is set into the options along with the Transport protocol. Options options = new Options(); options.setTo(targetEPR); options.setTransportInProtocol(Constants.TRANSPORT_HTTP); Now create a service client and pass these options to service client usi...

The purpose of this article is to talk about how to write web service and deploy it in Apache AXIS2. First step is downloading and installing apache axis2. There are two ways to use Apache AXIS2. 1. Install AXIS2 as a standalone server using the Standard Binary Distribution. 2. Deploy axis2.war and deploy it in a servlet container. We will be using the 2nd method in the article. To check the installation open the url http://localhost:8080/axis2 and you should be able to see the home page of apache axis2. Please locate the folder axis2\WEB-INF\services in exploded war file of axis2. This is the folder where you will copy the code of your service and it will get deployed in apache axis2. Lets us take a simple example. Write your service class. public class HelloWorld { public String sayHello(String firstName, String lastName) { System.out.println("Hello World Invoked"); MessageContext incomingContext = MessageContext.getCurrentMessageContext(); FileDataSourc...

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Apache Lucene is a high-performance, full-featured text search engine library. The API of lucene is very simple to use. Here is overview of some of the objects required to start using Apache Lucene. Document and Fields The class "org.apache.lucene.document.Document" is necessary container for the index. Lucene requires all indexed objects to provide an instance of Document. Each document defines one or several fields ( (org.apache.lucene.document.Field). Fields contain classified information about the document or metadata related to document. A sample classification is for example the creation date of a file, author of the document etc. These fields allow you to search later for a specific information in this classification. IndexWriter The class org.apache.lucene.index.IndexWriter creates the index. Via the method addDocument you can add an existing Document to the index. The constructor for IndexWriter expects the directory to store the index, and the analyzer f...

To call a struts action by Javascript on an event, you need to write a function which is invoked when the event occurs and this function makes an AJAX call. The AJAX call can send a request to the same URL which is provided in action attribute of form tag or html:form tag. e.g. In case your action URL is something like "/registerUserAction.do?action=forgetPasswordForward" that you provide in action attribute of html:form, you can pass the same url to the mentioned code snippet below: function makeRequest(url, callbackfunction) { var http_request = getXMLHttpObject(); url = url + "isComingFromAjax=true"; if (url.indexOf('?') != -1) { url = url + "&" ; } else { url = url + "?" ; } url = url + "isComingFromAjax=true"; http_request.onreadystatechange = callbackfunction; http_request.open('POST', url.substring(0, url.indexOf('?')), true); http_request.setRequestHeader('Content-Type...