NavelShip<\/strong> as Ship class would result in error in the sealed class hierarchy.<\/p>\n <\/p>\n
![\"Sealed](\"https:\/\/www.testingdocs.com\/questions\/wp-content\/uploads\/Sealed-classes-in-Java.png\" "\\"\\"")
<\/p>\n
<\/p>\n
![\"NavelShip](\"https:\/\/www.testingdocs.com\/questions\/wp-content\/uploads\/NavelShip.png\" "\\"\\"")
<\/p>\n
permits<\/h3>\n
permits clause allows us to specify the child classes for the sealed classes. The child class can be specified in separate files.<\/p>\n
\/\/ www.TestingDocs.com\r\npublic abstract sealed class Ship permits CargoShip,PassengerShip {\r\n protected String name;\r\n\r\n public Ship(String name) {\r\n this.name = name;\r\n }\r\n\r\n}\r\n<\/pre>\nPassengerShip<\/strong> and CargoShip<\/strong> can inherit the ship class.<\/p>\npublic final class PassengerShip extends Ship{\r\n private int noOfPassengers;\r\n\r\n public PassengerShip(String name,int p) {\r\n super(name);\r\n this.noOfPassengers=p;\r\n }\r\n\r\n public int getNoOfPassengers() {\r\n return noOfPassengers;\r\n }\r\n\r\n public void setNoOfPassengers(int noOfPassengers) {\r\n this.noOfPassengers = noOfPassengers;\r\n }\r\n\r\n @Override\r\n public String toString() {\r\n return \"Passenger Ship{\" +\r\n \"Cargo Weight in Tons=\" + getNoOfPassengers() +\r\n \", name='\" + name + '\\'' +\r\n '}';\r\n }\r\n}\r\n<\/pre>\nNote that Passenger ship is final class. So other classes cannot inherit from the final class PassengerShip<\/strong>. Sealed classes can extend other sealed classes. For example, due to the fewer number of Passenger ships government allows warships to carry passengers due to emergency.<\/p>\n <\/p>\n
public sealed class PassengerShip extends Ship permits WarShip{<\/strong><\/p>\npublic sealed class PassengerShip extends Ship permits WarShip{\r\n private int noOfPassengers;\r\n\r\n public PassengerShip(String name,int p) {\r\n super(name);\r\n this.noOfPassengers=p;\r\n }\r\n\r\n public int getNoOfPassengers() {\r\n return noOfPassengers;\r\n }\r\n\r\n public void setNoOfPassengers(int noOfPassengers) {\r\n this.noOfPassengers = noOfPassengers;\r\n }\r\n\r\n @Override\r\n public String toString() {\r\n return \"Passenger Ship{\" +\r\n \"Number of passengers=\" + getNoOfPassengers() +\r\n \", name='\" + name + '\\'' +\r\n '}';\r\n }\r\n}\r\n<\/pre>\n <\/p>\n
non-sealed<\/h3>\n
non-sealed opens up the inheritance to unknown child classes. This is like the normal inheritance in Java without specifying the keyword. or example, a non-sealed class would open the sealed hierarchy by allowing unknown classes to inherit the class.<\/p>\n
<\/p>\n
\/\/www.TestingDocs.com\r\npublic non-sealed class CargoShip extends Ship {\r\n private double cargoWeight; \/\/ kgs\r\n\r\n public CargoShip(String name, double w) {\r\n super(name);\r\n this.cargoWeight=w;\r\n }\r\n\r\n protected double convertToTons() {\r\n return this.cargoWeight\/1000;\r\n }\r\n\r\n @Override\r\n public String toString() {\r\n return \"Cargo Ship{\" +\r\n \"Cargo Weight in Tons=\" + convertToTons() +\r\n \", name='\" + name + '\\'' +\r\n '}';\r\n }\r\n}\r\n<\/pre>\n <\/p>\n","protected":false},"excerpt":{"rendered":"
Sealed Class Sealed classes in Java allow inheritance from the known sub classes that are specified by the permits keyword or defined in the same class file. If we mark a class as sealed it should have some sub classes specified using the permits clause or sub classes defined in the file.\u00a0 For example public […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[40],"tags":[],"class_list":["post-4909","post","type-post","status-publish","format-standard","hentry","category-java","has-post-title","has-post-date","has-post-category","has-post-tag","has-post-comment","has-post-author",""],"_links":{"self":[{"href":"https:\/\/www.testingdocs.com\/questions\/wp-json\/wp\/v2\/posts\/4909","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.testingdocs.com\/questions\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.testingdocs.com\/questions\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.testingdocs.com\/questions\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.testingdocs.com\/questions\/wp-json\/wp\/v2\/comments?post=4909"}],"version-history":[{"count":9,"href":"https:\/\/www.testingdocs.com\/questions\/wp-json\/wp\/v2\/posts\/4909\/revisions"}],"predecessor-version":[{"id":23645,"href":"https:\/\/www.testingdocs.com\/questions\/wp-json\/wp\/v2\/posts\/4909\/revisions\/23645"}],"wp:attachment":[{"href":"https:\/\/www.testingdocs.com\/questions\/wp-json\/wp\/v2\/media?parent=4909"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.testingdocs.com\/questions\/wp-json\/wp\/v2\/categories?post=4909"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.testingdocs.com\/questions\/wp-json\/wp\/v2\/tags?post=4909"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
![\"Project](\"https:\/\/www.testingdocs.com\/questions\/wp-content\/uploads\/Project-SDK.png\" "\\"\\"")
<\/p>\n