When and where java developers make use of a singleton class??
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The Singleton is a useful Design Pattern for allowing only one instance of your class, it's purpose is to control object creation, limiting the number to one but allowing the flexibility to create more objects if the situation changes. Since there is only one Singleton instance, any instance fields of a Singleton will occur only once per class, just like static fields.\n\nOften in designing a system, we want to control how an object is used, and prevent others (ourselves included) from making copies of it or creating new instances. For example, a central configuration object that stores setup information should have one and one only instance - a global copy accessible from any part of the application, including any threads that are running. Creating a new configuration object and using it would be fairly useless, as other parts of the application might be looking at the old configuration object, and changes to application settings wouldn't always be acted upon. I'm sure you can think of a other situations where a singleton would be useful - perhaps you've even used one before without giving it a name. It's a common enough design criteria (not used everyday, but you'll come across it from time to time). The singleton pattern can be applied in any language.
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Hi there;\n\nThere are many ways to use java to toss in a CRC. R you asking for the exact code?\nMwa-hahhahaha not so fast my friend.\nBut I can steer you in a direction if you want. :)\nCheck out the Sun Developer Network and good luck to you. :D
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This is not an isolated case, but you need to make sure you have the latest and greatest Java RunTime.\n\nI can help you there!  http://java.com - Grab the Java VM/JRE there, install it.\n\nAlso, http://ccleaner.com - download this to whipe off any junk that may be getting in the way.\n\nAnd http://fileforum.betanews.com/detail/Spybot_Search_and_Destroy/1043809773/1 Spybot will whipe off some of the extra spyware which may be messing with your PC.\n\nThen your off to the races. :O)
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static has two meanings.\n\n\nwhen applied to a method in a class, ... it means that the method will be available without having to instantiate a class.\n\nSay you have a class called: Foo. and a method called Bar(), if the method was static I would use the method like this:\n\nFoo.Bar();\n\nif the method isn't static, you use it like this...\n\nFoo f = new Foo();\nf.Bar();\n\ndo you see the difference? the same exact method is available to many instantiations of a class, while each instantiation has it's own method otherwise... \n\n\nAnother meaning of static is taken from C,C++ and can be applied to a variable.\n\nLets say you have a static variable, it's kinda like a global variable. It will keep it's value from the last run of the function... an example might make this all clear.\n\npublic class Test\n{\n\npublic static void Foo()\n{\nstatic int i = 0;\ni++;\nSystem.out.println(i);\n}\n\npublic void Foo2()\n{\nstatic int i = 0;\ni++;\nSystem.out.println(i);\n}\n\npublic void Foo3()\n{\nint i = 0;\ni++;\nSystem.out.println(i);\n}\npublic static void main(String args[])\n{\n     Test a = new Test();\n     Test b = new Test();\n\n     a.Foo2();\n     b.Foo2();\n     a.Foo2();     \n     b.Foo3();\n     b.Foo3();\n     b.Foo3();\n     Test.Foo();\n     Test.Foo();\n     Test.Foo();\n     \n}\n\n}\n\n\nif you run that program the output should be:\n\n1\n1\n2\n1\n1\n1\n1\n2\n3
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At least on the Linux/Solaris machines that I use,\nyou need to "wrap" your java class file with a\nscript which invokes the Java run time system.\nThis also gives you an opportunity to pass\nflags into the runtime (ie. to increase the\ndefault heap size, tweak the GC settings,\netc).\n\nFor example, for the class file "foo.class",\nthe script might be a single line like:\n\njava foo\n\n\nThen you would invoke the *script* rather\nthan trying to directly invoke the class\nfile.
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As blueJ is Java development environment, I think you are talking about java.\n\nIn java if you put a value already in map, old vlue is replaced by new one.
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Inner Classes \n\nInner classes let you define one class within another. \n\nThey provide a type of scoping for your classes since you can make one class a member of another class.\n\nJust as classes have member variables and methods, a class can also have member classes.\n\nclass Outer { \n/class Inner { } \n}// End of class \n\nif you compile it,\n%javac Outer.java\n\n\nyou’ll end up with two class files:\nOuter.class\nOuter$Inner.class\n\n\ne.g.\n\nclass Outer { \nprivate int x = 5;\n\npublic void outerMethod() {\nInner in = new Inner();\nin.innerMethod();\n}\n\nclass Inner {\npublic void innerMethod() {\nSystem.out.println("Outer variable x is " + x);\n}\n} \n}// End of class \n\n\nYou can create four different types of inner classes, based upon the how and the where of creation. \nNested top-level classes\nIf you declare a class within a class and specify the static modifier, the compiler treats the class just like any other top-level class. Any class outside the declaring class accesses the nested class with the declaring class name acting similarly to a package. eg, outer.inner. Top-level inner classes implicitly have access only to static variables. There can also be inner interfaces. All of these are of the nested top-level variety.\n\nMember classes\nMember inner classes are just like other member methods and member variables and access to the member class is restricted, just like methods and variables. This means a public member class acts similarly to a nested top-level class. The primary difference between member classes and nested top-level classes is that member classes have access to the specific instance of the enclosing class.\n\nLocal classes\nLocal classes are like local variables, specific to a block of code.Their visibility is only within the block of their declaration. In order for the class to be useful beyond the declaration block, it would need to implement a more publicly available interface.Because local classes are not members, the modifiers public, protected, private, and static are not usable.\n\nAnonymous classes \nAnonymous inner classes extend local inner classes one level further. As anonymous classes have no name, you cannot provide a constructor.
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Application server :- jboss,weblogic,websphere etc.These servvers implements J2EE standards  Webserver :- Apache webserver.Generally holds static html,images etc.\ndead lock occures in Threads
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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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private means the variable can be accessed only from within the same class as the variable.\nfriend means the variable can be accessed by code within the same project or component
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It allocates memory to the driver. Please refer : \n\nhttp://java.sun.com/j2se/1.4.2/docs/api/java/lang/Class.html#forName(java.lang.String,%20boolean,%20java.lang.ClassLoader)\nhttp://www.javageeks.com/Papers/ClassForName/index.html
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A constructor is a piece of code that is called when an instance of a class is created.\n\nYou usually use the constructor to initialize the object's attributes and state, perhaps with some parameters passed to it.\n\nConversely, the destructor is called when the object is destroyed.\n\nYou only need to explicitly define a destructor if you have cleanup code you want performed. Perhaps your instance needs to free up additional memory elsewhere, or you want to close an open file or something.\n\nExpansion of what humill_bca states: It is not required for a constructor to be public, and I don't believe should be one of its criteria. I don't know if its a language constraint of C++, but I code in Java, and we see private constructors all the time, espcially when implementing the Singleton Design pattern, or prior to Java 1.5, building your own enumerated type-safe classes, where we want to prevent the programmer from explicitely instantiating an instance of a class.
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Hi :\n\nI think you should downloud java software , you can find it in microsoft site , or at java sun site
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What do you mean by java class?
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Go back to Sun's Java site and head for the forums; that's the ideal place to get answers to questions of that nature. In fact, somebody asked a similar question in said forum:\n\nhttp://forum.java.sun.com/thread.jspa?threadID=460113&messageID=2107071
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If the Die.java application is not compiled you will need to do so. It should compile as Die.class. Then just make sure that class file (Die.class) is located in the same directory as the Java file you are working on which references Die.class.  You should not need to import it if this is the case since it is not part of the Java API.
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If J2EE was as bad as you think it is, why is it so widely used? Answer: it's not.\n\nIt's been a very long time since this technology could be accused of being generally inefficient. JIT and adaptive in-time compilers can actually recompile byte-code into assembley during runtime depending on how it's currently being used. This can produce faster execution in certain cases than C or C++.\n\nMost of the pain comes from starting the runtime, in an enterprise environment this is not an issue.\n\nPS. Remember it's just a specification. If you want to do Java just like C# (ie. compiled and ready to go as a binary), take a look at http://gcc.gnu.org/java/