Immutable classes in Java

package com.home;public class Address {private final String detail;public Address() {this.detail = "";}public Address(String detail) {this.detail = detail;}public String getDetail() {return detail;}@Overridepublic int hashCode() {return detail.hashCode();}@Overridepublic boolean equals(Object obj) {if (obj instanceof Address) {Address address = (Address) obj;if (this.getDetail().equals(address.getDetail())) {return true;}}return false;}}

Package com. home; public class Person {private final Name name; public Person (Name name) {super (); this. name = name;} public Name getName () {return name;} public static void main (String [] args) {Name n = new Name ("3 ", "Zhang"); Person p = new Person (n); System. out. println (p. getName (). getFirstName (); // change the firstName attribute value n of the Person object Name attribute. setFirstName ("nothing"); System. out. println (p. getName (). getFirstName ());}}

Name:

package com.home;public class Name {private String firstName;private String lastName;public Name() {super();}public Name(String firstName, String lastName) {super();this.firstName = firstName;this.lastName = lastName;}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;}}

Package com. home; public class Person {private final Name name; public Person (Name name) {super (); // set the name attribute to the Name object temporarily created, the firstName and lastName attributes of this object // they are the same as the firstName and lastName attributes of the passed name object. this. name = new Name (name. getFirstName (), name. getLastName ();} public Name getName () {// returns an anonymous object, the firstName and lastName attributes of this object // they are the same as the firstName and lastName attributes of the name attribute in this object. return new Name (name. getFirstName (), name. getLastName ();} public static void main (String [] args) {Name n = new Name ("3", "Zhang "); person p = new Person (n); System. out. println (p. getName (). getFirstName (); // change the firstName attribute value n of the Person object Name attribute. setFirstName ("nothing"); System. out. println (p. getName (). getFirstName ());}}

Package com. home; public class CacheImmutale {private final String name; private static CacheImmutale [] cache = new CacheImmutale [10]; private static int pos = 0; public CacheImmutale (String name) {super (); this. name = name;} public String getName () {return name;} public static CacheImmutale valueOf (String name) {// traverses cached objects for (int I = 0; I <pos; I ++) {// if the same instance already exists, the cached instance if (cache [I]! = Null & cache [I]. getName (). equals (name) {return cache [I] ;}// if the buffer pool is full if (pos = 10) {// overwrite the first cached object to cache [0] = new CacheImmutale (name); pos = 1; return cache [0];} else {// cache the newly created object, pos plus 1 cache [pos ++] = new CacheImmutale (name); return cache [pos-1];} @ Overridepublic int hashCode () {return name. hashCode () ;}@ Overridepublic boolean equals (Object obj) {if (obj instanceof CacheImmutale) {CacheImmutale ci = (CacheImmutale) obj; if (name. equals (ci. getName () {return true;} return false;} public static void main (String [] args) {CacheImmutale c1 = CacheImmutale. valueOf ("hello"); CacheImmutale c2 = CacheImmutale. valueOf ("hello"); System. out. println (c1 = c2); // The output result is true }}

Package com. home; public class Person {private final Name name; public Person (Name name) {super (); // set the name attribute to the Name object temporarily created, the firstName and lastName attributes of this object // they are the same as the firstName and lastName attributes of the passed name object. this. name = new Name (name. getFirstName (), name. getLastName ();} public Name getName () {// return the name attribute of the current instance to return name;} public static void main (String [] args) {Name n = new Name ("3", "Zhang"); Person p = new Person (n); System. out. println (p. getName () + "" + p. getName (). getFirstName (); // change the firstName attribute value n of the Person object Name attribute. setFirstName ("nothing"); System. out. println (p. getName () + "" + p. getName (). getFirstName ());}}