Saturday, December 31, 2011
Friday, December 30, 2011
Reading XML file in java using SAX Parser is little different than reading xml file in Java with DOM parser which we had discussed in last article of this series. This tutorial is can be useful for those who are new to the java world and got the requirement for read an xml file in java in their project or assignment, key feature of java is it provides built in class and object to handle everything which makes our task very easy. Basically this process of handling XML file is known as parsing means break down the whole string into small pieces using the special tokens.
Parsing can be done using two ways:
Thursday, December 29, 2011
Wednesday, December 28, 2011
How to parse xml file in Java or how to read xml file in java is one of common need of a Java Developer working with enterprise Java application which uses XML for data representation, messaging and data transfer. Java has good support to handle XML files and XML Documents and you can read XML File in Java, create or write to XML file in Java by using various XML parsers available. Reading XML file is little bit different than reading text or binary file in Java but it uses same concept of File class.
Monday, December 26, 2011
Sunday, December 25, 2011
Observer design pattern in Java is a fundamental core Java pattern where Observe watch for any change in state or property of Subject. For Example Company updates all its shareholders for any decision they make here Company is Subject and Shareholders are Observers, any change in policy of company and Company notifies all its Shareholders or Observer. This was simple real world explanation of Observer pattern. In this article we will in detail what is Observer Design pattern, what is benefit of Observer design Pattern, Example or Observer pattern in Java and few other points. Just like Decorator design Pattern and Factory Pattern in Java, Observer pattern is also used in JDK.
Friday, December 23, 2011
Method Overloading vs Method Overriding
Though name of method remains same in case of both method overloading and overriding, main difference comes form the fact that method overloading is resolved during compile time, while method overriding is resolved at runtime. Also rules of overriding or overloading a method is different in Java. For example, private, static and final method cannot be overriding in Java but you can still overload them. For overriding both name and signature of method must remain same, but in for overloading method signature must be different. Last but not the least difference between them is that call to overloaded methods are resolved using static binding while call to overridden method is resolved using dynamic binding in Java. By the way, Method overloading and method overriding in Java is two important concept in Java which allows Java programmer to declare method with same name but different behavior. Method overloading and method overriding is based on Polymorphism in Java. In case of method overloading, method with same name co-exists in same class but they must have different method signature, while in case of method overriding, method with same name is declared in derived class or sub class.Method overloading is resolved using static binding in Java at compile time while method overriding is resolved using dynamic binding in Java at runtime. In short When you overload a method in Java its method signature got changed while in case of overriding method signature remains same but a method can only be overridden in sub class. Since Java supports Polymorphism and resolve object at run-time it is capable to call overridden method in Java. By the way difference between method overloading and overriding is also one of the popular Java design question and appear in almost all levels of Java interviews.
Tuesday, December 20, 2011
java.net.BindException: Address already in use: JVM_Bind is a common exception in Java with application trying to connect on a particular port and some other processes either Java or non Java is already connected on that port. You can get "Address already in use: JVM_Bind" error while doing remote debugging in Java in Eclipse, when Eclipse trying to connect to remote Java application, when you are starting tomcat and another instance of tomcat is listening on port 8080 you will get java.net.BindException: Address already in use: JVM_Bind:8080.
Monday, December 19, 2011
Main method in Java is the first programming method a Java programmer knows when he starts learning Java programming language.have you ever thought about why main method in Java is public, static and void, of-course Yes, since most of us first learn C and C++ than we move to Java in our programming path we familiar with main method but in Java main method is slightly different it doesn't return any value like in C it returns int, main method is public static and void Why? In this post we will try to find answer of these questions and have an idea of one of the most popular questions in Java why main method is declared Static.
Friday, December 16, 2011
I am sure this is one of those most optimistic title you can think of but that is what my first thought after seeing apple introductory video of Siri, there new voice recognition and task completion service integrated on Apple Iphone4s. I was amazed with smoothness and accuracy of Siri as shown on that video. You just say siri what's whether, find me new restaurant, traffic status and you get a response you are looking for, this looks to me a new way of searching web and technology. Asking questions is more natural than typing on Google and believe if Siri kicks of like that you will suddenly have more search volume via siri than google, though only limiting factor is not everybody has Apple Iphone4s with them :). People are also thinking Siri as Google Killer let's see.
Wednesday, December 14, 2011
Monday, December 12, 2011
Friday, December 9, 2011
Wednesday, December 7, 2011
Tuesday, December 6, 2011
Java has excellent support for reading from file and writing to file in Java. In last post we have seen how to create file and directory in Java and now we will see how to read content from file in java and how we will write text into file in Java. File provides persistent solution to Java developer; in almost every Java application you need to store some of the data in persistent may be its user configuration, system configuration or related to state of application but without persistence no enterprise Java application can buildup. Normally Database is preferred choice for storing data persistently but in high frequency trading one doesn’t have liberty to afford network latency to travel database and latency introduced by database itself, though database still offer best choice for historical data , transactional details related to orders and trades are commonly stored in In Memory files provided by Java.nio API.
Monday, December 5, 2011
java.rmi.MarshalException: CORBA MARSHAL, which was bothering me from last couple of days while working. I thought to put this solution post similar to my earlier post How to solve OutofMEmroyError in Java and Fixing ClassNotFoundException in Java. RMI is still used in many places and many times it create too much problem and chew-up your lot of time to find exact cause and solution.
Sunday, December 4, 2011
Inside Search: Search quality highlights: new monthly series on a...: Today we’re publishing another list of search improvements, beginning a monthly series where we’ll be sharing even more details about the al...
Saturday, December 3, 2011
How to create File and directory in Java is probably the first things come in mind when we exposed to file system from Java. Java provides rich IO API to access contents of File and Directory in Java and also provides lots of utility method to create file, delete file, read from file, and write to file or directory. Anybody who wants to develop application in Java should have a solid understanding of IO and Networking package. In this Java File Tutorial we will basics of File and Directory in Java, How to Create File and Directory in Java, Utility methods provided by File API and Common Exception or Error you will face during File and Directory Creation or access time. Creating File is different than creating Thread in java as you don’t have to implement any interface for making a Class as File in Java.
File in Java is also getting its place on various core java interviews questions specially after introduction of java.nio package and concepts like In Memory Files, we will discuss about those in probably another blog post but what it confirms is importance of knowledge of File IO for java programmer.
Friday, December 2, 2011
Factory design pattern in Java one of the core design pattern which is used heavily not only in JDK but also in various Open Source framework such as Spring, Struts and Apache along with decorator design pattern in Java. Factory Design pattern is based on Encapsulation object oriented concept. Factory method is used to create different object from factory often refereed as Item and it encapsulate the creation code. So instead of having object creation code on client side we encapsulate inside Factory method in Java. One of the best examples of factory pattern in Java is BorderFactory Class of Swing API. In this Design pattern tutorial we will see What is Factory method design pattern in Java, What are main advantages of factory pattern in Java , Code example of Factory design pattern and What problem Factory pattern solves in Java or when to use Factory design pattern. This article is in continuation of my design pattern article as 10 OOPS and SOLID design principles java programmer should know and How to use Observer pattern in Java