Is there inheritance in Java?
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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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If you've never used an object-oriented language before, you need to understand the underlying concepts before beginning to write code. You need to know what an object is, what a class is, how objects and classes are related, and how objects communicate by using messages. The first few sections of this chapter describe the concepts behind object-oriented programming. The last section shows how these concepts translate into code. \nWhat Is an Object?\nAn object is a software bundle of related variables and methods. Software objects are often used to model real-world objects you find in everyday life. \nWhat Is a Message?\nSoftware objects interact and communicate with each other using messages. \nWhat Is a Class?\nA class is a blueprint or prototype that defines the variables and the methods common to all objects of a certain kind. \nWhat Is Inheritance?\nA class inherits state and behavior from its superclass. Inheritance provides a powerful and natural mechanism for organizing and structuring software programs. \nWhat Is an Interface?\nAn interface is a contract in the form of a collection of method and constant declarations. When a class implements an interface, it promises to implement all of the methods declared in that interface. \nHow Do These Concepts Translate into Code?\nThis section looks at a small applet, and shows you the code that creates objects, implements classes, sends messages, establishes a superclass, and implements an interface.
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This link might help\nhttp://ekhtml.sourceforge.net/\n\nRequired classes already exist in Java, and most probably in C++ as well.
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JVM will not create any additional constructors apart from those that u have declared in the class.The only case is that if u are not supplying any constuctor then jVM will create a default constructor.
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Go to http://java.sun.com and you can learn all about it. Its the JAVA information superhighway.\n\nAlso check out http://www.java.com
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Your object will be passed by reference because\nthat's how Java passes all objects.  Only the\nprimitive types like "int" are passed by value.
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An interface contains only the signatures of methods, delegates or events. The implementation of the methods is done in the class that implements the interface, as shown in the following example:\n\ninterface ISampleInterface\n{\n    void SampleMethod();\n}\n\nclass ImplementationClass : ISampleInterface\n{\n    // Explicit interface member implementation: \n    void ISampleInterface.SampleMethod()\n    {\n        // Method implementation.\n    }\n\n    static void Main()\n    {\n        // Declare an interface instance.\n        ISampleInterface obj = new ImplementationClass();\n\n        // Call the member.\n        obj.SampleMethod();\n    }\n}\nAn interface can inherit from one or more base interfaces.\n\nWhen a base type list contains a base class and interfaces, the base class must come first in the list.\n\nA class that implements an interface can explicitly implement members of that interface. An explicitly implemented member cannot be accessed through a class instance, but only through an instance of the interface.
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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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C) ABC, somthing1, something2 must be interface for the expression to be legal.\n\nThough java doesn't supports multiple inheritence for class, an interface can extend as many interface as needed. You can try compiling. But there is also a reason behind it.\nJava does not supports multiple inheritence because in diamond inheritence ( B and C extends A and D extends both B and C) it can cause ambiguity( as two copies of members of A would present in D).\nThis is not so for interface as there can't be ambiguity as all refer to same copy. So Java supports multiple inheritence for Inetrface
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Well, huh.  \n\nOkay, let's say we're making a dog simulator with OOP.  So we might have various "objects" in the game in order to give structure to our program; in this case, "dog" could be a primary object.  But anything that exists in our program would also be an object -- street, fire hydrant, owner, leash, policeman, etc.\n\nOur dog object will have various properties, methods, and events.  Properties are things that describe the object (possibly uniquely), methods are things the object can actually do, and events are things that can happen to the object that it can respond to.  For example, "color" might be a property, "smell(something)" might be a method, and "owner picks up leash" an event.\n\nA constructor is simply the most basic method for any object that actually creates a new unique object.  In this case anytime we define a new dog object we will call the constructor for that object, in which we might set some default properties (ie set color = "black") and call some methods to establish the object within the program framework.  For example, we might use a constructor to register the new dog object in the list of possible "encounter" events that can happen to other dogs.\n\nObviously this is a very basic introduction. The best way to familiarize yourself with OOP is to design a few very very basic programs -- let's say a program that runs a mouse through a maze.  Imagine all the objects, all the properties for those objects, all the methods those objects will have to do, and all the events the objects will have to respond to, and write them all out.  \n\nThen program something yourself in your favorite programming language and find out all the things you forgot to include  :)
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I think you should click on this link http://java.sun.com/docs/books/tutorial/java/concepts
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Was Form1 created by a method in Form2 - or vice versa?\n\nIf so, you could pass a reference of the one form to the other via the Form's constructor. Let's assume that Form1 creates and calls Form2:\n\nIn Form2: (New Method)\n------------------------------------------------\nPrivate MyParent As Form1 '<--- Reference to Form1\n\nPublic Sub New(Parent As Form1)\n  InitializeComponents ' <--- This has to be here\n  MyParent = Parent ' <--- Storing the reference for later use!\nEnd Sub\n------------------------------------------------\nIn Form1: (This is the creation of Form2)\n------------------------------------------------\nDim NewForm As New Form2(Me)\nNewForm.Show()\n------------------------------------------------\nThen when you want to send the info back to the other form, you have a reference to it:\n\nMyParent.TextBox1.Text = Whatever\n\n------------------------------------------------\n\nIf Form1 does not directly create Form2 (or vice versa), they can find eachother through a common ancestor... and they MUST have a common ancestor since all the forms were launched by a single application.\n\nIn my humble opinion, using a global variable to do this common task is a bit of a kludge - so learn the right way to do it! When you start writing applications of any size, you'll see that global variables turn out to be a horrible way to pass information.\n\nIf you need more detailed help, I'd be happy to offer it up!
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Obviously the idea behind multiple inheritance is to\nallow objects to have the behaviors of multiple types.\nHowever, how often have you actually been able to\ninherit the *behavior* (ie. the implementation) from\nmultiple parent types, as opposed to just the *interface*?\n\nIn some cases, you can get the semantics you want by\nincluding on object of one of the parent types.  And\nwhen appropriate, Java allows you to implement an\ninterface for another "parent" type without even pretending\nthat you could inherit the implementation.  \n\nAs for why Java never had multiple inheritance, in my\nopinion, it is confusing and error prone.
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Invoking Object's clone method on an instance that does not implement the Cloneable interface results in the exception CloneNotSupportedException being thrown.\n\nBy convention, classes that implement this interface should override Object.clone (which is protected) with a public method. See Object.clone() for details on overriding this method.\n\nNote that this interface does not contain the clone method. Therefore, it is not possible to clone an object merely by virtue of the fact that it implements this interface. Even if the clone method is invoked reflectively, there is no guarantee that it will succeed. \n\nThat means you cannot simply say implements Cloneable since Cloneable has absolutely no methods. Especially not clone. The Object Interface does have clone. Which has the structure of: protected Object clone() throws CloneNotSupportedException\n\nAs the docs say:\nThe class Object does not itself implement the interface Cloneable, so calling the clone method on an object whose class is Object will result in throwing an exception at run time.
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No you cant. Its a server-side application that is using JAVA listeners and classes to run it. It uses Java to support it.\n\nYou cannot copy it, sorry.
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You first need to import the class (or classes) and then you will be able to use their methods or  create objects with those classes.\n\nexample: import java.util.*
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Choosing interfaces and abstract classes is not an either/or proposition. If you need to change your design, make it an interface. However, you may have abstract classes that provide some default behavior. Abstract classes are excellent candidates inside of application frameworks. \n\nAbstract classes let you define some behaviors; they force your subclasses to provide others. For example, if you have an application framework, an abstract class may provide default services such as event and message handling. Those services allow your application to plug in to your application framework. However, there is some application-specific functionality that only your application can perform. Such functionality might include startup and shutdown tasks, which are often application-dependent. So instead of trying to define that behavior itself, the abstract base class can declare abstract shutdown and startup methods. The base class knows that it needs those methods, but an abstract class lets your class admit that it doesn't know how to perform those actions; it only knows that it must initiate the actions. When it is time to start up, the abstract class can call the startup method. When the base class calls this method, Java calls the method defined by the child class. \n\nMany developers forget that a class that defines an abstract method can call that method as well. Abstract classes are an excellent way to create planned inheritance hierarchies. They're also a good choice for nonleaf classes in class hierarchies.