In Java Singleton class or design pattern restricts the instantiation of a class to a singular instance.
Following example shows a classic Singleton design pattern implementation:
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public class ClassicSingleton { private static ClassicSingleton instance = null; protected ClassicSingleton() { // Exists only to defeat instantiation. } public static ClassicSingleton getInstance() { if (instance == null) { instance = new ClassicSingleton(); } return instance; } } |