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Tuesday, September 30, 2008

Java Abstract Methods : Return type

Consider an abstract class declaring an abstract method. Let the return type of the method be Object. Now lets say, a class extends this abstract class and defines this method. What should be the return type of this method to override the base abstract method? ;D, it can be anything!!


public abstract class AbstractClassA{
    public abstract Object getDataForDoingSomething();
}

public abstract class SClassA extends AbstractClassA{
    public List getDataForDoingSomething() {           
                return new ArrayList();
    }
}

3 comments:

  1. I thought this can be used and i configured in the log4j.xml, but only to my disappointment log4j does not recognize elements rollingPolicy and triggeringPolicy. But there DTD, log4j.dtd, had these elemets.
    [...]
    So, there was nothing about the rollingPolicy or triggeringPolicy, though there DTD defines them.

    -----

    Hello,

    I had exactly the same problem which I fix by upgrading log4j.jar to 1.2.15 (previously I had 1.2.13).

    Now log4j recognize rollingPolicy...
    So much for backward compatibility :o)

    N.

    ReplyDelete
  2. :) I think you posted on wrong post.

    ReplyDelete