abstract class

[venkatesh pendharkar]

HI
I would like to know is there any way we can create instance of abstract class.Beacuse we can define normal methods(non-static) in an abstract class,so how can we call this methods without creating instance of the class.And if we cant call these methods ,then whats the use of defining normal methods in abstract class.
Also i want to know what is the use of defining constructor in an abstract class???If we cant instantiate this class,then its constructer is never going to get called.

[Shaan Shar]

Originally posted by venkatesh pendharkar:
HI
I would like to know is there any way we can create instance of abstract class.Beacuse we can define normal methods(non-static) in an abstract class,so how can we call this methods without creating instance of the class.And if we cant call these methods ,then whats the use of defining normal methods in abstract class.
Also i want to know what is the use of defining constructor in an abstract class???If we cant instantiate this class,then its constructer is never going to get called.

Hope this example would help you some how and you may proceed further.

Carefully read this example and then you may want to raise your another question clearly as it is vast topic....

public class Sample extends abc {
public Sample() {
System.out.println(" Hi");
}
public static void main(String[] args) {
Sample sam = new Sample();
// here s is an object of abstract class abc which is referring to Sample reference
abc s = new Sample();
System.out.println(" abc.str: " + sam.str);
}
}
abstract class abc {
String str;
public abc() {
System.out.println(" hello World");
str = getValue();
}
public int add(int m, int n) {
return (m + n);
}
private String getValue() {
return "Hello World";
}
}

[venkatesh pendharkar]

Thanks for the reply Sharma ji.
SO that means when we create a sample object ;constructor of class abc gets called & thus we can get construcor of abstract class run(by creating object of its subclass).And the non abstract methods will be directly available to the subclass to use.
So i think normal methods in the abstract class will be available only to its subclass & we cant use them anywhere outside the class(by creating instance).
am i correct sharmaji?

[Andy Morris]

Pretty much yes, that's the purpose of abstract classes.

However, whatever access modifiers you apply to methods in an abstract class still apply. So if an abstract class has a public method, then any calling code can call that method on an instance, but if a private method exists in the abstract class, then not even subclasses wont be able to call it.
[ November 15, 2006: Message edited by: Andy Morris ]

[venkatesh pendharkar]

I got it Andy,thanks for helping me out in this