{"id":2161,"date":"2020-03-17T17:34:06","date_gmt":"2020-03-17T17:34:06","guid":{"rendered":"https:\/\/www.h2kinfosys.com\/blog\/?p=2161"},"modified":"2020-03-18T14:07:05","modified_gmt":"2020-03-18T14:07:05","slug":"introduction-to-polymorphism","status":"publish","type":"post","link":"https:\/\/www.h2kinfosys.com\/blog\/introduction-to-polymorphism\/","title":{"rendered":"Introduction to Polymorphism"},"content":{"rendered":"

Polymorphism means one name can have many forms.<\/span><\/p>\n

To understand this, let us take an example, suppose you have a smartphone for communication purposes. The communication mode may vary. It can be anything that may be a call, a text message, a picture message, mail, etc. But the goal is the same in all communication modes, that is, communication. This is called <\/span>Polymorphism, <\/b>where the purpose is the same but with different approaches. An example of polymorphism is Method Overriding.<\/span><\/p>\n

Method Overriding<\/b><\/h2>\n

Method Overriding is used to define a superclass method in a subclass.<\/span><\/p>\n

Some basic rules for Method Overriding<\/b><\/p>\n

    \n
  • The signature of the method, i.e., method name, parameter list, and return type should be the same<\/span><\/li>\n
  • If a method present in the superclass is defined as private, then the subclass can make it public but not vice versa.<\/span><\/li>\n<\/ul>\n

    What is Dynamic Polymorphism?<\/b><\/h2>\n

    Dynamic Polymorphism is the process in which multiple methods are defined with the same name and signature in both superclass and subclass.\u00a0<\/span><\/p>\n

    Example of Dynamic Polymorphism:<\/span><\/h3>\n

    Doctor obj = new Surgeon();
    \n<\/span>Consider the statement
    \n<\/span>obj.treatPatient();<\/span><\/p>\n

    Here the variable “obj” refers to the object of the parent class, but the object is pointing to the method of the child class.<\/span><\/p>\n

    \"\"<\/p>\n

    obj.treatPatient() will then execute treatPatient() method of the subclass named Surgeon<\/span><\/p>\n

    If we use a subclass reference to call a method, then the method that is going to be invoked will be decided by the JVM.<\/span><\/p>\n

    For example, obj here is a reference object to Doctor, it will call the method of Surgeon, as obj here points to a Surgeon object<\/span><\/p>\n

    All these things are decided during run-time and hence called as\u00a0<\/span>dynamic\u00a0<\/b>or\u00a0<\/span><\/i>run-time polymorphism.<\/b><\/p>\n

    But what if the treatPatient method in the Surgeon class wants to access the functionality defined in Doctor class and then want to perform its specific functionality?<\/span>
    \n<\/span>
    \n<\/span>This can be achieved using the super keyword\u00a0to access methods of the superclass from the subclass.<\/span>
    \n<\/span>
    \n<\/span>The treatPatient method in the Surgeon class will then be written as:<\/span><\/p>\n

    treatPatient(){
    \n<\/span>\u00a0\u00a0\u00a0super.treatPatient();
    \n<\/span>\u00a0\u00a0\u00a0\u00a0\u00a0\/\/add code specific to Surgeon<\/span><\/p>\n

    The complete code will be :<\/span><\/p>\n

    \"\"<\/p>\n

    \"\"<\/p>\n

    Difference between Static & Dynamic Polymorphism<\/b><\/h2>\n

    <\/h2>\n\n\n\n\n\n\n
    \n

    Static Polymorphism<\/b><\/h4>\n<\/td>\n

    		\n

    Dynamic Polymorphism<\/b><\/h4>\n<\/td>\n<\/tr>\n

    Related to method overloading.<\/span><\/td>\nRelated to method overriding.<\/span><\/td>\n<\/tr>\n
    Errors get resolved at compile time only.<\/span><\/td>\nErrors get resolved at run time.<\/span><\/td>\n<\/tr>\n
    void sum (int a , int b);
    \n<\/span>void sum (float a, double b);
    \n<\/span>int sum (int a, int b); \/\/compiler gives error.<\/span><\/td>\n    		\/\/reference of parent pointing to child object
    \n<\/span>Doctor obj = new Surgeon();
    \n<\/span>\/\/ method of child called
    \n<\/span>obj.treatPatient();<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

     <\/p>\n","protected":false},"excerpt":{"rendered":"

    Polymorphism means one name can have many forms. To understand this, let us take an example, suppose you have a smartphone for communication purposes. The communication mode may vary. It can be anything that may be a call, a text message, a picture message, mail, etc. But the goal is the same in all communication […]<\/p>\n","protected":false},"author":1,"featured_media":2176,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[42],"tags":[429,427,428],"class_list":["post-2161","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-java-tutorials","tag-dynamic-polymorphism","tag-polymorphism","tag-static-polymorphism"],"_links":{"self":[{"href":"https:\/\/www.h2kinfosys.com\/blog\/wp-json\/wp\/v2\/posts\/2161","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.h2kinfosys.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.h2kinfosys.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.h2kinfosys.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.h2kinfosys.com\/blog\/wp-json\/wp\/v2\/comments?post=2161"}],"version-history":[{"count":0,"href":"https:\/\/www.h2kinfosys.com\/blog\/wp-json\/wp\/v2\/posts\/2161\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.h2kinfosys.com\/blog\/wp-json\/wp\/v2\/media\/2176"}],"wp:attachment":[{"href":"https:\/\/www.h2kinfosys.com\/blog\/wp-json\/wp\/v2\/media?parent=2161"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.h2kinfosys.com\/blog\/wp-json\/wp\/v2\/categories?post=2161"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.h2kinfosys.com\/blog\/wp-json\/wp\/v2\/tags?post=2161"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}