{"id":4020,"date":"2024-03-13T07:49:43","date_gmt":"2024-03-13T07:49:43","guid":{"rendered":"https:\/\/www.silicloud.com\/blog\/how-to-write-an-abstract-class-in-java\/"},"modified":"2025-07-31T00:33:31","modified_gmt":"2025-07-31T00:33:31","slug":"how-to-write-an-abstract-class-in-java","status":"publish","type":"post","link":"https:\/\/www.silicloud.com\/blog\/how-to-write-an-abstract-class-in-java\/","title":{"rendered":"Java Abstract Class: How to Write"},"content":{"rendered":"

In Java, an abstract class is a class that cannot be instantiated, and it can contain both abstract and non-abstract methods. The steps to write an abstract class in Java are as follows:<\/p>\n

    \n
  1. Declare an abstract class using the keyword “abstract”.<\/li>\n
  2. In an abstract class, you can include both abstract methods, which are declared using the keyword “abstract,” and non-abstract methods, which are implemented directly.<\/li>\n
  3. If a class inherits an abstract class and does not implement the abstract methods, then that class must also be declared as an abstract class.<\/li>\n<\/ol>\n

    Here is a simple example demonstrating how to write an abstract class.<\/p>\n

    \/\/ \u62bd\u8c61\u7c7b<\/span>\r\nabstract<\/span> class<\/span> Shape<\/span> {\r\n    \/\/ \u62bd\u8c61\u65b9\u6cd5<\/span>\r\n    public<\/span> abstract<\/span> double<\/span> getArea<\/span>()<\/span>;\r\n\r\n    \/\/ \u975e\u62bd\u8c61\u65b9\u6cd5<\/span>\r\n    public<\/span> void<\/span> printShape<\/span>()<\/span> {\r\n        System.out.println(\"This is a shape.\"<\/span>);\r\n    }\r\n}\r\n\r\n\/\/ \u7ee7\u627f\u62bd\u8c61\u7c7b<\/span>\r\nclass<\/span> Circle<\/span> extends<\/span> Shape<\/span> {\r\n    private<\/span> double<\/span> radius;\r\n\r\n    public<\/span> Circle<\/span>(double<\/span> radius)<\/span> {\r\n        this<\/span>.radius = radius;\r\n    }\r\n\r\n    \/\/ \u5b9e\u73b0\u62bd\u8c61\u65b9\u6cd5<\/span>\r\n    @Override<\/span>\r\n    public<\/span> double<\/span> getArea<\/span>()<\/span> {\r\n        return<\/span> Math.PI * radius * radius;\r\n    }\r\n}\r\n\r\npublic<\/span> class<\/span> Main<\/span> {\r\n    public<\/span> static<\/span> void<\/span> main<\/span>(String[] args)<\/span> {\r\n        Circle<\/span> circle<\/span> =<\/span> new<\/span> Circle<\/span>(5<\/span>);\r\n        System.out.println(\"Area of circle: \"<\/span> + circle.getArea());\r\n        circle.printShape();\r\n    }\r\n}\r\n<\/code><\/pre>\n
    In the above example, Shape is an abstract class that contains an abstract method getArea() and a non-abstract method printShape(). The Circle class inherits from the Shape class and implements the getArea() method. The Circle class is instantiated in the Main class, where its methods are called.<\/p>\n","protected":false},"excerpt":{"rendered":"
    In Java, an abstract class is a class that cannot be instantiated, and it can contain both abstract and non-abstract methods. The steps to write an abstract class in Java are as follows: Declare an abstract class using the keyword “abstract”. In an abstract class, you can include both abstract methods, which are declared using […]<\/p>\n","protected":false},"author":11,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_import_markdown_pro_load_document_selector":0,"_import_markdown_pro_submit_text_textarea":"","footnotes":""},"categories":[1],"tags":[3120,3122,3123,180,3121],"class_list":["post-4020","post","type-post","status-publish","format-standard","hentry","category-uncategorized","tag-abstract-class-java","tag-abstract-methods","tag-java-inheritance","tag-java-programming","tag-oop-concepts"],"yoast_head":"\nJava Abstract Class: How to Write - Blog - Silicon Cloud<\/title>\n<meta name=\"description\" content=\"Learn to write abstract classes in Java with our step-by-step guide. 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