confusion with Design Pttern in java

[sandeepsai39]

Hi to all, Iam learning Design patterns in java, i have a doubt with Design Pattern,Design pattern defined as open for source to extension and closed for
modification.I didn't see any difference between this pattern and Observer Pattern or Strategy Pattern,we can use this Pattern instead of Design Pattern why it is introdused and what is mean by closed for modification in source from which we are extending.

[JosAH]

Hi to all, Iam learning Design patterns in java, i have a doubt with Design Pattern,Design pattern defined as open for source to extension and closed for
modification.I didn't see any difference between this pattern and Observer Pattern or Strategy Pattern,we can use this Pattern instead of Design Pattern why it is introdused and what is mean by closed for modification in source from which we are extending.

Closed for modification implies that you don't have any need to modify the original source code; open for extension means that you can add functionality to the pattern (mostly done through extension of classes).

You can't do both with the Observer/Observable pattern. The other pattern is ususally implemented as a 'framework'.

kind regards,

Jos

[sandeepsai39]

thank u jos i got your point .