The Singleton Design Pattern

You're such a typical newb; learn something new and you're suddenly an expert on the subject.

he said LIE-BARRY at 1:24. ouch

Singleton is the most well known anti pattern in OO. Please dont encourage it. Plus the example of db pools is shit, what happens when you want to employ diffent strategys in different environements, or mock the behaviour?

Singleton == SHITE

waste of time , this guy is so close to the monitor

The Object Singleton will not dispose until program exit. why because of using 'STATIC'

how we can assure that this class will not instantiate by another object?

NOTICE the "PRIVATE Constructor" he wrote of a "Singleton CLASS"

but not recommend this in the multithreading.

Learn. English.

I find it original ! and kind !

You forgot to talk about the singleton in a multi-threaded environment. If you don't do it properly, you will get multiple instances!

Yes, I indeed didn't mention that. However, this is an introduction for those who haven't yet been introduced to design patterns, so I'm keeping it simple. The wikipedia entry I refer to has a wide range of solutions for all kinds of languages, including a few multi-thread safe ones for java. I hope you find what you need there.

If you implement a singleton in Java please dont do the assignment of your singleton variable in the constructor. This is an unneccessary waste of resources (check for null every time you want to get your singleton). Do it at its declaration. This also prevents you from synchronizing access to the singleton to make it threadsafe.