{"id":1088,"date":"2016-03-07T11:53:22","date_gmt":"2016-03-07T11:53:22","guid":{"rendered":"http:\/\/abhiandroid.com\/java\/?p=1088"},"modified":"2016-03-07T11:53:22","modified_gmt":"2016-03-07T11:53:22","slug":"super-keyword","status":"publish","type":"post","link":"https:\/\/abhiandroid.com\/java\/super-keyword.html","title":{"rendered":"Super Keyword In Java With Examples"},"content":{"rendered":"

In java the keyword super <\/strong>refers to the superclass of the class in which super appears. A subclass inherits the accessible variables and methods from its superclass, but the constructors of the superclass are not inherited in the subclass. They can only be invoked from constructors of subclass using the keyword super<\/strong>.<\/p>\n

The superclass constructor call must be the first statement in the body of childclass constructor. If one does not specify super<\/strong>, the compiler implicitly inserts super();<\/strong> at the beginning of the childclass\u2019s default constructor to call the superclass\u2019s default constructor.<\/p>\n

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Syntax of Super<\/strong><\/h4>\n

Following syntax is used to call superclass constructor:<\/p>\n

super([arguments])<\/pre>\n
Here the arguments enclosed in square bracket are optional.<\/p>\n
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Program Examples of Super Keyword<\/strong><\/h4>\n
Program 1:<\/strong><\/span> This program shows how to call super class constructor <\/strong>using \u201csuper\u201d keyword in Java.<\/p>\n
Step 1: <\/strong><\/span>First we create a class SuperClass <\/strong>in which we take a constructor:<\/p>\n
class SuperClass\r\n\r\n{\r\n\r\n  public SuperClass(String str)\r\n\r\n  { \r\n\r\n    System.out.println(\"Super Class Constructor \" + str);\r\n\r\n  }\r\n\r\n}<\/pre>\n
Step 2: <\/strong><\/span>Second we create a class SubClass <\/strong>which extends the class SuperClass <\/strong>and we use super keyword to call the SuperClass constructor:<\/p>\n
class SubClass extends SuperClass\r\n\r\n{\r\n\r\n   public SubClass(String str)\r\n\r\n   {\r\n\r\n     super(str); \/\/calls SuperClass class constructor\r\n\r\n     System.out.println(\"Sub Class Constructor \" + str);\r\n\r\n   }\r\n\r\n}<\/pre>\n
Step 3: <\/strong><\/span>Third we create a class SuperConst <\/strong>in which we make an object of class SubClass<\/strong>:<\/p>\n
class SuperConst\r\n\r\n{\r\n\r\n   public static void main(String args[])\r\n\r\n   {\r\n\r\n     SubClass obj = new SubClass(\"called\");\r\n\r\n   }\r\n\r\n}<\/pre>\n
Output<\/strong>:<\/strong><\/p>\n
Super Class Constructor called\r\nSub Class Constructor called<\/pre>\n
Program 2:<\/strong><\/span> This programs shows how to call super class method <\/strong>using \u201csuper\u201d in java.<\/p>\n
Step 1: <\/strong><\/span>First we create a class SuperClass<\/strong> in which we take a show() method:<\/p>\n
class SuperClass\r\n\r\n{\r\n\r\n   void show()\r\n\r\n  {\r\n\r\n    System.out.println(\"Super Class method has been called\");\r\n\r\n  }\r\n\r\n}<\/pre>\n
Step 2: <\/strong><\/span>Second we create a class SubClass<\/strong> which extends the class SuperClass<\/strong> and use the super keyword to call the SuperClass class method:<\/p>\n
class SubClass extends SuperClass\r\n\r\n{\r\n\r\n  void show()\r\n\r\n  {\r\n\r\n    super.show();\r\n\r\n    System.out.println(\"Sub Class method has been called\");\r\n\r\n  }\r\n\r\n}<\/pre>\n
Step 3: <\/strong><\/span>Third we create a class SuperMethod<\/strong> in which we make an object of class SubClass<\/strong>:<\/p>\n
class SuperMethod\r\n\r\n{\r\n\r\n  public static void main(String args[])\r\n\r\n {\r\n\r\n\u00a0  SubClass obj = new SubClass();\r\n\r\n   obj.show();\r\n }\r\n\r\n}<\/pre>\n
Output:<\/strong><\/p>\n
Super Class method has been called\r\nSub Class method has been called<\/pre>\n
Program 3:<\/strong><\/span> This program shows how to access super class variables <\/strong>using \u201csuper\u201d in java.<\/p>\n
Step 1: <\/strong><\/span>First we create a class SuperClass<\/strong> in which we take a variable:<\/p>\n
class SuperClass\r\n\r\n{\r\n\r\n  int x = 30;\r\n\r\n}<\/pre>\n
Step 2: <\/strong><\/span>Second we create a class SubClass<\/strong> which extends the class SuperClass<\/strong> and use the super keyword to call the SuperClass class variable:<\/p>\n
class SubClass extends SuperClass\r\n\r\n{\r\n\r\n  void show()\r\n\r\n {\r\n\r\n   int x = super.x;\r\n\r\n   System.out.println(\"The value of x is : \" + x);\r\n\r\n }\r\n\r\n}<\/pre>\n
Step 3: <\/strong><\/span>Third we create a class SuperVar<\/strong> in which we make an object of class SubClass<\/strong>:<\/p>\n
class SuperVar\r\n\r\n{\r\n\r\n   public static void main(String args[])\r\n\r\n  {\r\n\r\n    SubClass obj = new SubClass();\r\n\r\n    obj.show();\r\n\r\n  }\r\n\r\n}<\/pre>\n
Output:<\/strong><\/p>\n
The value x is : 30<\/pre>\n
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Rules of Super Keyword<\/strong><\/h4>\n