Java important Question - 9

Q) Can we declare a class as static ?

          We can't declare a top-level class as static however an inner class can be declared as static. If inner class is declared as static,it's called  static nested class. The static nested class is same as any other top-level class and is nested for only packaging convenience. Also when we declare a class as 'static' then it can be referenced without the use of an object.

Q) What is static import ?

          static import is a feature introduced in java version 5.0 that allows members defined in a class as public static to be used in Java code without specifying the class in which the field is defined. If we have to use any static variable or method from other class, usually we import the class and then use the method/variable with class name. We can do the same thing by importing the static method or variable only and then use it in the class as if it belong to it.

import static java.lang.System.*;

class StaticImportExample {

public static void main(String args[]) {

.......

out.println("Hello"); //( Now no need of system.out)

out.println("Java");

}

}

Q) What is difference between import and static import ?

          The import allows the java programmer to access classes of a package without package qualification whereas the static import features allows to access the static members of a class without the class qualification. The import provides accessibility to classes and interface whereas static import provides accessibility to static members of the class. 

Q) Can we import same package/class two times? Will the JVM load the package twice at Runtime ?

          A package or class can be imported multiple times in a program code. JVM and compiler will not create any issue.Moreover JVM automatically loads the class internally once regardless of times it is called in the program.

Ab talk call - free phone call & world wide calling