Wt is a Collection class in Java ? are collection class and collection interface are same ?
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A collection in any language is a container that will hold other objects.  Examples of container classes in Java are List, Map, Set.  These are actually implemented as interfaces, they just define the basic methods that are expected for each of the different types of collections.  Concrete implementations for each of these interfaces would be HashSet, ArrayList, LinkedList, HashMap, TreeMap, TreeSet (there are others, but these are the most popular).\n\nThe simple answer to your question in regards to whether an interface and a class are the same is NO.  An interface is a definition of methods.  A class is an implemetation of those and probably other methods.  The syntax for this in Java would look like:\n\nclass X implements Y\n\nWhere X is the implemetation of the Y interface.  That is exactly how the collection classes are implemented in the JDK, the class declaration for ArrayList follows:\n\npublic class ArrayList<E> extends AbstractList<E>\n        implements List<E>, RandomAccess, Cloneable, java.io.Serializable\n\nNow, keep in mind that you CAN use an interface to access an instance of a class (an object).  For example:\n\nList myList = new ArrayList();\n\nList is an interface, ArrayList is a class.  Actually this is the intention of interfaces, separation of model and implementation. You could use a LinkedList in your code if you wrote your code this way just by changing the line that declares myList and no other code would have to be touched:\n\nList myList = new LinkedList();
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method is like a function if you familiar with c or c++.\nMethod is called like a function the same way you did in c or c++\nMethod in class is a method which associates with its data and other members like functions, objects, etc.\n\nWhile object method is a method which is invoked or called by the object as a referrence. It can also calls a method from another class, depending on your hierarchy, where the other class must either be on top(base class) or same level or at the bottom as long as it has the linkage. To do this, u must use a polymorphism technique (which mostly learn at the institute).\n\nPlease refer to the reference book for this --I'm out of my memory for this!! I've been graduated for a long time ago:)\nBut if you have a technical problem to be solved, you can ask me.\nThis is my email:-> k_mz79@yahoo.com
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What do you mean by java class?
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There are in fact two types of inheritance in Java:\n - Interface implementation:\n. . . . A Class inherits the method signatures and constants in any interface it implements\n - Class extension:\n. . . . A Class can extend one other class (or an interface can extend one other interface)
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Rudrajyoti, you are completely wrong.\n\nBoxing is converting a value-type (those simple values, think of integers and floating point values as good examples, that live in stack space) into reference-types (objects with support for polimorphy, etc, that live in the heap of a program).\n\nThe operation is performed implicitly. For instance, when you create a message by calling:\n\nint year = 2006;\nint age = 2006 - 1974;\nstring.Format("This is the year {0} and I will be {1}.", (object)year, (object)age);\n\nBoth integral variables are allocated on the stack of whatever function we're into. But when the string.Format is executed, the cast (could be implicit, I've made it explicit to clarify the point) to object implies creating new instances of Int32 on the heap as real objects with separate state and able to perform things like "ToString()" on specific ways, etc.\n\nThe rationale behind this is that the CLR/MISL did not want to buy the "everything is an object on the heap" moto that makes Smalltalk crawl and be unusable. Small little numbers belong on the stack. However, if you want objects from them, you can have them.
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We need the notion of a parent class (from which we can inherit) that is prohibitted from being instantiated.\n\nThink about abstract classes as semicomplete generalised implementations that can not exist as objects on their own, they can only exist as parts of child objects. \n\nFor example, think of a "Shape" hierarchy with subclasses such as Rectangle, Circle, Line etc. As shapes share data and implementation (i.e. coordinates, ability to paint themselves) it makes sense generalising, that is, creating a parent class (Shape) that contains all common aspects of the shapes. So at this point "Shape" is just a superclass.\nIt does not make sense however being able to instantiate an object of the class Shape because it misses critical information. To prohibit it,we make the class an abstract class.\nFor quick info on abstract classes & methods look at:\nhttp://www.thanassis.com/java/java%20training%20course/java%20and%20object%20orientation.htm#JavaAbstractClasses\nhope it helps :)
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Better way is to creat an instance of Random class.\nIt has methods, nextInteger(), nextdouble(), and others.
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all types in java are signed.  that's how it was designed.  i have found it to be a problem only very rarely.
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class tree {\npublic:\n int countNodes(){\n    if (root == NULL) { return 0; }\n    return this.countNodes(root);\n }\nprivate:\n int countNodes(Node in){\n    if (in == NULL){ return 0; }\n    else { return countNodes(root->leftSubtree) + countNodes(root->rightSubtree) + 1; }\n }\nNode* root;\n};
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java usees wrapper classes...Byte,Integer..they are in java.lang package..\n\nin each such class there is one memeber \nstatic int SIZE\n\nusing that u can find out..\n\neg.System.out.println(Byte.SIZE);\n//The number of bits used to represent a byte value in two's complement binary form\n\nSIMILARITY FOR OTHER DATA TYPES..\n\ncheck out documentation site..or if u have already downloaded doc..then use that..
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Briefly, there are Anonymous Methods, Iterators, Partial Classes, and Generics. I think Generics is the best new feature in C# 2.0 because it gives you more flexibility (like templates in C++) and it's a lot easier to share the same code for many different tasks.
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Try visiting Javadoc. you will find there.
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1. Official information: http://www.w3.org/2002/ws/\n2. If you are going to use java - http://java.sun.com/webservices/ will show you how you can use it.\n3. Here is a short example: http://java.sun.com/j2ee/1.4/docs/tutorial/doc/Session3.html
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I created these pages when I was teaching Java to C++ programmers. I translated it to wiki format many years later.\n\nhttp://wiki.java.net/bin/view/Main/WoodHarterNotes\n\nHope that helps.
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You can't create real objects for interfaces. You can have a reference for a object.\nConnection c;\n\nc = DriverManager.getConnection (url,"myLogin", "myPassword");\n\nThis is what happens - \nYour driver class (oracle/db2/sql/ whichever) makes a object which implements the interface Connection. The reference of this real object is returned by the getConnection method.\n\nThis is the real object which you access through the referecnce of the Connection interface. \n\nSo you cannot create an object of the Connection interface, only reference a real object through it.
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An adapter class is a class that provides a dummy (empty) implementation for an interface. That way someone who wants to implement the interface but does not want or does not know how to implement all methods, can use the adapter class instead, and only override the methods he is interested in.\n\nThe most common use of adapters is in event listeners, classes that define callback for various events. For example java.awt.event.MouseAdapter (http://java.sun.com/j2se/1.5.0/docs/api/java/awt/event/MouseAdapter.html) is an adapter for the java.awt.event.MouseListener event listener interface (http://java.sun.com/j2se/1.5.0/docs/api/java/awt/event/MouseListener.html)
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Have you tried getting the object as a FileInfo or something like that and then checking the type based on that?\nThats the best I can think of.