In this post, we will see about the difference between equals and == in java.<\/p>\n
This is most asked java interview question for fresher<\/a> or 2-year experienced<\/a> java developer and it might be confusing sometimes. Let’s try to understand each quickly.<\/p>\n Equality operator can be used to compare primitives but when you compare objects using ==, it just compares reference not the actual content of the objects.<\/p>\n If you want to compare the actual content of the object, then you need to override equals method in your class. If you do not override object’s class equals method, then it behaves same as "==" and compares references only.<\/p>\n Let’s understand difference between equals() and == in java.<\/p>\n Let’s take quick example in case of String and custom object.<\/p>\n String is most common scenario where equals and == methods are used.<\/p>\n When you run above program, you will get below output<\/p>\n It is very much similar to String. Let’s create Employee class and override equals method. If two employees have same name and age then they will be considered as same.<\/p>\n Create another class for Employee comparison<\/p>\n When you run above program, you will get below output<\/p>\n That’s all about difference between equals() and == in java.<\/p>\n","protected":false},"excerpt":{"rendered":" In this post, we will see about the difference between equals and == in java. This is most asked java interview question for fresher or 2-year experienced java developer and it might be confusing sometimes. Let’s try to understand each quickly. Equality operator “==” Equality operator can be used to compare primitives but when you […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[144,27],"tags":[],"_links":{"self":[{"href":"https:\/\/java2blog.com\/wp-json\/wp\/v2\/posts\/6720"}],"collection":[{"href":"https:\/\/java2blog.com\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/java2blog.com\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/java2blog.com\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/java2blog.com\/wp-json\/wp\/v2\/comments?post=6720"}],"version-history":[{"count":0,"href":"https:\/\/java2blog.com\/wp-json\/wp\/v2\/posts\/6720\/revisions"}],"wp:attachment":[{"href":"https:\/\/java2blog.com\/wp-json\/wp\/v2\/media?parent=6720"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/java2blog.com\/wp-json\/wp\/v2\/categories?post=6720"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/java2blog.com\/wp-json\/wp\/v2\/tags?post=6720"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\nEquality operator “==”<\/span><\/h2>\n
\nEquals methods<\/span><\/h2>\n
\nDifference between equals() and == in java<\/span><\/h2>\n
\n
\nExample<\/span><\/h2>\n
Equals and == in case of String<\/h3>\n
package org.arpit.java2blog;\n\npublic class StringEqualsAndOpetatorMain {\n\n public static void main(String[] args) {\n String name1=new String(\"John\");\n String name2=new String(\"John\");\n\n \/*Even though content of objects is same, it will\n * return false, as name1 and name2 points to different objects\n *\/\n System.out.println(name1==name2);\n \/*Equals method compares content, so this will return true\n *\/\n System.out.println(name1.equals(name2));\n System.out.println(\"===================\");\n\n name2=name1;\n\n \/*Now name1 and name2 both point to same reference\n * so this will return true\n *\/\n System.out.println(name1==name2);\n \/*Equals method compares content, so this will return true\n *\/\n System.out.println(name1.equals(name2));\n }\n\n}\n<\/pre>\n
\ntrue
\n===================
\ntrue
\ntrue<\/div>\nEquals and == in case of Custom objects<\/h3>\n
package org.arpit.java2blog;\n\npublic class Employee {\n String name;\n int age;\n\n public Employee(String name, int age) {\n this.name=name;\n this.age=age;\n }\n public String getName() {\n return name;\n }\n public void setName(String name) {\n this.name = name;\n }\n public int getAge() {\n return age;\n }\n public void setAge(int age) {\n this.age = age;\n }\n\n @Override\n public boolean equals(Object obj) {\n if (this == obj)\n return true;\n if (obj == null)\n return false;\n if (getClass() != obj.getClass())\n return false;\n Employee other = (Employee) obj;\n if (age != other.age)\n return false;\n if (name == null) {\n if (other.name != null)\n return false;\n } else if (!name.equals(other.name))\n return false;\n return true;\n }\n}\n<\/pre>\npackage org.arpit.java2blog;\n\npublic class EmployeeEqualsAndOpetatorMain {\n\n public static void main(String[] args) {\n Employee emp1=new Employee(\"John\",18);\n Employee emp2=new Employee(\"John\",18);\n\n \/*Even though content of objects is same, it will\n * return false, as name1 and name2 points to different objects\n *\/\n System.out.println(emp1==emp2);\n \/*Equals method compares content, so this will return true\n *\/\n System.out.println(emp1.equals(emp2));\n System.out.println(\"===================\");\n\n emp2=emp1;\n\n \/*Now name1 and name2 both point to same reference\n * so this will return true\n *\/\n System.out.println(emp1==emp2);\n \/*Equals method compares content, so this will return true\n *\/\n System.out.println(emp1.equals(emp2));\n }\n\n}\n<\/pre>\n
\ntrue
\n===================
\ntrue
\ntrue<\/div>\n