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Best Practice

메모리 신경안써, 쓰레드 신경안써 대충 대충

→ 필드 Ver - public static final 필드 제공


public class Singleton{

	public static final Singleton INSTANCE = new Singleton();

	private Singleton() {}
}

조금 신경 좀 쓸까?

→ Bill Pugh Singleton Implementation


//inner static class 활용
class Singleton
{
	private Singleton() {}

  private static class SingletonHolder {
		private static final Singleton INSTANCE = new Singleton();
	}

	public static Singleton getInstance() {
			return SingletonHolder.Instance;
	}
}

초 정석

→ Enum


public enum Elvis {
	INSTANCE;

	...
}