Design Patterns

Singleton Design Pattern:
A Singleton is a class that can be instantiated only one time in a JVM. It ensures that only one instance of the class available and provides global point of access.

Example:

public class MySingleton {

private static MySingleton myInstance; //static instance

private MySingleton() {
} //private constructor

public static MySingleton getInstance() {
if(myInstance == null)
myInstance = new MySingleton(); //checking for exsisting instance
return myInstance;
}
}


In any class to use the above singleton class:

MySingleton singletonFrame = MySingleton.getInstance();