java 简单的单例 实现

public class Test {

	public static void main(String[] args) {
		
		Name name = Name.getNameInstance();
		name.setFirstName("J.K");
		name.setLastName("Rolling");
			
		Name name2 = Name.getNameInstance();
		
		
		System.out.println(name);
		System.out.println(name2);
		
		System.out.println(name == name2);
		System.out.println(name.equals(name2));
	}
}

class Name {
	private String firstName;
	private String lastName;
	
	
	private Name() {	
	}

	private static Name name = null;
	
	public static Name getNameInstance() {
		if (name == null) {
			name = new Name();
		}
		return name;
	}
	
	/**
	 * 单例模式 核心代码--------------------
	 * 
	 *
	 *
	 */
//	private static final Name name = new Name();
//	
//	public static Name getNameInstance() {
//		return name;
//	}
	
	public String getFirstName() {
		return firstName;
	}
	
	public void setFirstName(String firstName) {
		this.firstName = firstName;
	}
	
	public String getLastName() {
		return lastName;
	}
	
	public void setLastName(String lastName) {
		this.lastName = lastName;
	}
	
	public String toString() {
		return getFirstName() + " " + getLastName();
	}	
}