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The static keyword signifies that the method belongs to the class and not any of its objects. Hence, the JVM does not have to create an object of that class before beginning execution. Imagine how the JVM would create an object and invokes its method even before the class execution starts. That is why the main method is static and is the starting point of any java application.
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If you write int in place of void in public static void main what happand?
If you change the return type (to any type no only int) of your 'main' method the jvm no longer can use this method as a entry point for your program. It seems to be no errors, but your program do nothing.
Can main method be non-static?
No, the reason is simple: A method marked as a static means, that you don't need create an instance (create an object with the 'new' operator) in order to use it. The main method is the entry point for a java application, therefor there is nothing after you call it. no one who can create an object of the type of your class and call the main method. So the jvm must call the main method with no object reference.
Why using the name main for main method in java?
If you run an java file(as an .class or .jar file) there's always 1 method being called: The main(String[] args) method.The method is only called once.Example of an main method:public static void main(String args[]) throws IOException {LoggingBootstrap.bootstrap();gui = new GUI();}In this case it only bootstraps the logger and uses the constuctor method of GUI(the graphical user interface of the program)
What is the parameter specification for the public static void main method?
The Main method is the method in which execution to any java program begins. A main method declaration looks as follows: public static void main(String args[]){ } The method is public because it be accessible to the JVM to begin execution of the program. It is Static because it be available for execution without an object instance. you may know that you need an object instance to invoke any method. So you cannot begin execution of a class without its object if the main method was not static. It returns only a void because, once the main method execution is over, the program terminates. So there can be no data that can be returned by the Main method The last parameter is String args[]. This is used to signify that the user may opt to enter parameters to the java program at command line. We can use both String[] args or String args[]. The Java compiler would accept both forms.
Public static void main String arg means?
The Main method is the method in which execution to any java program begins.A main method declaration looks as follows:public static void main(String args[]){}The method is public because it be accessible to the JVM to begin execution of the program.It is Static because it be available for execution without an object instance. you may know that you need an object instance to invoke any method. So you cannot begin execution of a class without its object if the main method was not static.It returns only a void because, once the main method execution is over, the program terminates. So there can be no data that can be returned by the Main methodThe last parameter is String args[]. This is used to signify that the user may opt to enter parameters to the java program at command line. We can use both String[] args or String args[]. The Java compiler would accept both forms.--------------------------------------------------------------------------------------------------------------User : ALPHAZEROYou can also use like thisclass alpha{public static void main(String...args){S.o.p("HOW");}}[S.o.p = System.out.println]Still i don't know explain why but i know its work you can also try like this if you already know how its work please post here or mail me zalpha@rocketmail.com--------------------------------------------------------------------------------------------------------------
Why you use main method when you can use static method?
The main method is called by the jvm when your program is executed. The main method is a static method: public static void main(String[] args) {} A static method is method that can be run without instantiate the class (creating an object from it) The main method is a static method. No other static method could replace it's functionality. PS By static method do you mean static initialiser? I often use static initialisers instead of a main method, but in these cases you must still have a main method, albeit an empty one ie. public static void main(String[] args) {} Notice that the method has an empty body A main method must be used if you intend to accept parameters at run time from the jvm.
How nonstatic fields can be used in public static void main of a class?
They can't be. If you want to use a non-static field in a static method, you need an instance of the class to reference. class MyClass { int myX; static int staticX; public static void main(String[] args) { // We can directly reference staticX whenever we want. staticX = 10; // We need an instance of MyClass to use myX. MyClass mc = new MyClass(); mc.myX = 10; } }
If you write int in place of void in public static void main what happand?
If you change the return type (to any type no only int) of your 'main' method the jvm no longer can use this method as a entry point for your program. It seems to be no errors, but your program do nothing.
Can main method be non-static?
No, the reason is simple: A method marked as a static means, that you don't need create an instance (create an object with the 'new' operator) in order to use it. The main method is the entry point for a java application, therefor there is nothing after you call it. no one who can create an object of the type of your class and call the main method. So the jvm must call the main method with no object reference.
Why do you use static key word in java main method?
Static means that something is done at compile time instead of when the object is instantiated, so you would therefore call a static method (doSomething()) through the class name rather than the object name. class A{ public static void B(){ } public void C(){ } } Let's say A instance = new A(); To access B you would say A.B(), while to access C you would say instance.C();
Why using the name main for main method in java?
If you run an java file(as an .class or .jar file) there's always 1 method being called: The main(String[] args) method.The method is only called once.Example of an main method:public static void main(String args[]) throws IOException {LoggingBootstrap.bootstrap();gui = new GUI();}In this case it only bootstraps the logger and uses the constuctor method of GUI(the graphical user interface of the program)
What is the parameter specification for the public static void main method?
The Main method is the method in which execution to any java program begins. A main method declaration looks as follows: public static void main(String args[]){ } The method is public because it be accessible to the JVM to begin execution of the program. It is Static because it be available for execution without an object instance. you may know that you need an object instance to invoke any method. So you cannot begin execution of a class without its object if the main method was not static. It returns only a void because, once the main method execution is over, the program terminates. So there can be no data that can be returned by the Main method The last parameter is String args[]. This is used to signify that the user may opt to enter parameters to the java program at command line. We can use both String[] args or String args[]. The Java compiler would accept both forms.
what is the difference between final and static keywords?
static: we can use the keyword static either to method or to a variable. when we declare to a method,(eg: public static void main(String args[]),we can use this method without any object. when we use to a variable,there will be only one instance of that variable irrespective of how many objects that get created of that class. Final: Usage of final to method or to a variable makes them as constant. It's value cannot be changed...
Public static void main String arg means?
The Main method is the method in which execution to any java program begins.A main method declaration looks as follows:public static void main(String args[]){}The method is public because it be accessible to the JVM to begin execution of the program.It is Static because it be available for execution without an object instance. you may know that you need an object instance to invoke any method. So you cannot begin execution of a class without its object if the main method was not static.It returns only a void because, once the main method execution is over, the program terminates. So there can be no data that can be returned by the Main methodThe last parameter is String args[]. This is used to signify that the user may opt to enter parameters to the java program at command line. We can use both String[] args or String args[]. The Java compiler would accept both forms.--------------------------------------------------------------------------------------------------------------User : ALPHAZEROYou can also use like thisclass alpha{public static void main(String...args){S.o.p("HOW");}}[S.o.p = System.out.println]Still i don't know explain why but i know its work you can also try like this if you already know how its work please post here or mail me zalpha@rocketmail.com--------------------------------------------------------------------------------------------------------------
How do you Write a java program that computes the sum of the first ten postive integers?
you can use the condition statement like for(i=0:i<=10;i++)
Why should main be declared static and is declaring it public and void not sufficient?
The static modifier means that it does not have to be instantiated to use it. Before a program runs there are technically no objects created yet, so the main method, which is the entry point for the application must be labeled static to tell the JVM that the method can be used without having first to create an instance of that class. Otherwise, it is the "Which came first, the chicken or the egg?" phenomenon. Your main method should be declared as follows: public static void main (String[] args) { lots of your java code... } As we know, java is a pure OOP , that means everything should be in the class, main. Aso, because main is itself a function, static member functions should not refer to objects of that class. But we can access static functions through classname itself, as: class TestMain { public static void main(String args[]) { body; } } Now, cmd>javac TestMain.java cmd>java TestMain as we know the static member functions has to call through its class name. That's why the programme name must be same as the class name ,where we wrote the main function. Another important point is : static variables or member functions will load during class. That means before creating any instances(objects), the main function is the first runnable function of any program which we run manually, such as : cmd>java TestMain(run) if , any sharing information.
Define the concepts of threads.?
The Java language includes a powerful threading facility built into the language. You can use the threading facility to: · Increase the responsiveness of GUI applications · Take advantage of multiprocessor systems · Simplify program logic when there are multiple independent entities · Perform blocking I/O without blocking the entire program You can create Threads in Java using two ways - Implementing the Runnable Interface or by Extending the Thread class A Sample Thread program: public class TwoThreads { public static class Thread1 extends Thread { public void run() { System.out.println("A"); System.out.println("B"); } } public static class Thread2 extends Thread { public void run() { System.out.println("1"); System.out.println("2"); } } public static void main(String[] args) { new Thread1().start(); new Thread2().start(); } }
