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();}}