java.util.Calender Abstract confusion

[Mohd Fuzail]

java.util.Calender is an abstract class with a method getInstance() which returns an instance of the Calender class

If an class is abstract, how can we get an instance of that class without implementing the abstract class

[Deepak Bala]

The getInstance method will return the implemented class for you. This way of getting an instantiated object is to make sure that it cant be instantiated like this...

Calender c = new Calender();

Thats because classes with private constructors cant be instantiated with the preceding code.

You can control the type of object to send, and you can instantiate it properly before sending it.

[Mohd Fuzail]

how can i see implemeted code of getInstance() method of java.util.Calender??

[Deepak Bala]

Have a look at the src.zip file that comes with the JDK. Browse the right package to find Calender.java ( I wouldnt go that far to see the implementation though )

[Guy Allard]

In the directory where the JDK is installed, there should be a file named 'src.zip'.

Unzip it.

Most of the Java source code is in there.

Guy

:-) Ah well, I am late with this post......
[ September 24, 2006: Message edited by: Guy Allard ]

[Barry Gaunt]

Run this code:

import java.util.*;
public class TestCalendar
{
    public static void main(String[] args) {
        Calendar c = Calendar.getInstance(new Locale("ge", "CH")); // german, Switzerland
        System.out.println(c.getClass().getName());
    }
}
    

You can then see what type of Calendar the getInstance() method returns.
Change the Locale parameters to see if you can get another type of Calendar.
[ September 24, 2006: Message edited by: Barry Gaunt ]