Java program’s
main
method has to be declared static
because keyword static
allows main to be called without creating an object of the class in which the main
method is defined. If we omitstatic
keyword before main
Java program will successfully compile but it won’t execute.
For a little detailed description, look at the usual signature of Java’s
main
methodpublic static void main (String[] args)
Above code line begins defining the
main
method. This is the line at which the program will start executing. All Java applications begin execution by calling main
.
The
public
keyword is an access specifier, which allows the programmer to control the visibility of class members. When a class member is preceded by public
, then that member may be accessed by code outside the class in which it is declared. In this case, main
must be declared as public
, since it must be called by code outside of its class when the program is started. The keyword static
allows main
to be called without having to instantiate a particular instance of the class. Without having declared main
methodstatic
, your program will successfully compile but won’t execute and report error at run time. This is necessary since main
is called by the Java interpreter before any objects are made. The keyword void
simply tells the compiler that main
does not return a value. The main
is the method called when a Java application begins. Keep in mind that Java is case-sensitive. Thus, Mainis different from main. It is important to understand that the Java compiler will compile classes that do not contain a main
method. But the Java interpreter has no way to run these classes. So, if you had typed Main instead of main, the compiler would still compile your program. However, the Java interpreter would report an error because it would be unable to find the main
method.
public is the visibility. This can be public, private, protected or (if you omit a value) default.
static is a special [optional] keyword that indicates that this method can be called without creating an instance of this class. Without it, you have to instantiate this class and call this method from the resulting object.
void is the return type of this method, indicating that this method doesn’t return anything. Methods must have a return type.
main( … ) is the name of this method. Methods have to be named. The parentheses indicate that this is a method.
String[] args is a single parameter for the method. String[] is the type of the parameter, indicating an array of Strings. args is the name of the parameter. Parameters must be named.
No comments:
Post a Comment