{"id":479,"date":"2021-01-07T16:28:41","date_gmt":"2021-01-07T16:28:41","guid":{"rendered":"https:\/\/bhiggs.x10hosting.com\/PracticalJavaProgramming\/?page_id=479"},"modified":"2021-01-07T16:32:00","modified_gmt":"2021-01-07T16:32:00","slug":"final-classes-methods","status":"publish","type":"page","link":"https:\/\/bhiggs.x10hosting.com\/PracticalJavaProgramming\/course-topics\/inheritance-polymorphism\/final-classes-methods\/","title":{"rendered":"Final Classes &#038; Methods"},"content":{"rendered":"<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_85 counter-hierarchy ez-toc-counter ez-toc-grey ez-toc-container-direction\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">Table of Contents<\/p>\n<label for=\"ez-toc-cssicon-toggle-item-6a3f9704857b0\" class=\"ez-toc-cssicon-toggle-label\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #999;color:#999\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/label><input type=\"checkbox\"  id=\"ez-toc-cssicon-toggle-item-6a3f9704857b0\"  aria-label=\"Toggle\" \/><nav><ul class='ez-toc-list ez-toc-list-level-1 ' ><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/bhiggs.x10hosting.com\/PracticalJavaProgramming\/course-topics\/inheritance-polymorphism\/final-classes-methods\/#Final_classes_Preventing_Inheritance\" >Final\u00a0classes: Preventing Inheritance<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/bhiggs.x10hosting.com\/PracticalJavaProgramming\/course-topics\/inheritance-polymorphism\/final-classes-methods\/#Final_methods\" >Final\u00a0methods<\/a><ul class='ez-toc-list-level-4' ><li class='ez-toc-heading-level-4'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/bhiggs.x10hosting.com\/PracticalJavaProgramming\/course-topics\/inheritance-polymorphism\/final-classes-methods\/#Reasons_for_making_classes_or_methods_final\" >Reasons for making classes or methods&nbsp;final<\/a><\/li><\/ul><\/li><li class='ez-toc-page-1 ez-toc-heading-level-3'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/bhiggs.x10hosting.com\/PracticalJavaProgramming\/course-topics\/inheritance-polymorphism\/final-classes-methods\/#Final_fields_data\" >Final\u00a0fields (data)<\/a><\/li><\/ul><\/nav><\/div>\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Final_classes_Preventing_Inheritance\"><\/span><strong>Final<\/strong>\u00a0classes: Preventing Inheritance<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Sometimes, you will wish to prevent someone from deriving a class from one of your classes.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">A class that cannot be used as a superclass is called a&nbsp;<em><strong>final class<\/strong><\/em>.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">To specify that a class is <em>final<\/em>, you use the&nbsp;<strong>final&nbsp;<\/strong>keyword:<\/p>\n\n\n\n<pre class=\"wp-block-preformatted\"><strong>public final class President extends Employee\n{\n    \/\/ ...\n}<\/strong><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Final_methods\"><\/span><strong>Final<\/strong>\u00a0methods<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">It is also possible to declare a specific method in a class&nbsp;<strong>final<\/strong>, meaning that no subclass can override that method.<\/p>\n\n\n\n<p class=\"wp-block-paragraph\">All methods in a&nbsp;<strong>final&nbsp;<\/strong>class are automatically&nbsp;<strong>final<\/strong>.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Reasons_for_making_classes_or_methods_final\"><\/span><strong>Reasons for making classes or methods&nbsp;final<\/strong><span class=\"ez-toc-section-end\"><\/span><\/h4>\n\n\n\n<ol class=\"wp-block-list\"><li>Efficiency<br>Dynamic binding is expensive. If the compiler knows that a method will not be overridden, it can optimize calls to that method (by inlining it, etc.)<\/li><li>Safety<br>By disabling dynamic binding, you can remove a lot of uncertainty from your code.<\/li><\/ol>\n\n\n\n<h3 class=\"wp-block-heading\"><span class=\"ez-toc-section\" id=\"Final_fields_data\"><\/span><strong>Final<\/strong>\u00a0fields (data)<span class=\"ez-toc-section-end\"><\/span><\/h3>\n\n\n\n<p class=\"wp-block-paragraph\">Remember that&nbsp;<code><strong>final<\/strong><\/code>&nbsp;data members of a class, once initialized, cannot be changed.&nbsp; Class constants are typically&nbsp;<code><strong>static final<\/strong><\/code>&nbsp;fields.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Final\u00a0classes: Preventing Inheritance Sometimes, you will wish to prevent someone from deriving a class from one of your classes. A class that cannot be used as a superclass is called a&nbsp;final class. To specify that a class is final, you use the&nbsp;final&nbsp;keyword: public final class President extends Employee { \/\/ &#8230; } Final\u00a0methods It is [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":0,"parent":61,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_eb_attr":"","_uag_custom_page_level_css":"","ocean_post_layout":"left-sidebar","ocean_both_sidebars_style":"","ocean_both_sidebars_content_width":0,"ocean_both_sidebars_sidebars_width":0,"ocean_sidebar":"ocs-course-topics-sidebar","ocean_second_sidebar":"0","ocean_disable_margins":"enable","ocean_add_body_class":"","ocean_shortcode_before_top_bar":"","ocean_shortcode_after_top_bar":"","ocean_shortcode_before_header":"","ocean_shortcode_after_header":"","ocean_has_shortcode":"","ocean_shortcode_after_title":"","ocean_shortcode_before_footer_widgets":"","ocean_shortcode_after_footer_widgets":"","ocean_shortcode_before_footer_bottom":"","ocean_shortcode_after_footer_bottom":"","ocean_display_top_bar":"default","ocean_display_header":"default","ocean_header_style":"","ocean_center_header_left_menu":"0","ocean_custom_header_template":"0","ocean_custom_logo":0,"ocean_custom_retina_logo":0,"ocean_custom_logo_max_width":0,"ocean_custom_logo_tablet_max_width":0,"ocean_custom_logo_mobile_max_width":0,"ocean_custom_logo_max_height":0,"ocean_custom_logo_tablet_max_height":0,"ocean_custom_logo_mobile_max_height":0,"ocean_header_custom_menu":"0","ocean_menu_typo_font_family":"0","ocean_menu_typo_font_subset":"","ocean_menu_typo_font_size":0,"ocean_menu_typo_font_size_tablet":0,"ocean_menu_typo_font_size_mobile":0,"ocean_menu_typo_font_size_unit":"px","ocean_menu_typo_font_weight":"","ocean_menu_typo_font_weight_tablet":"","ocean_menu_typo_font_weight_mobile":"","ocean_menu_typo_transform":"","ocean_menu_typo_transform_tablet":"","ocean_menu_typo_transform_mobile":"","ocean_menu_typo_line_height":0,"ocean_menu_typo_line_height_tablet":0,"ocean_menu_typo_line_height_mobile":0,"ocean_menu_typo_line_height_unit":"","ocean_menu_typo_spacing":0,"ocean_menu_typo_spacing_tablet":0,"ocean_menu_typo_spacing_mobile":0,"ocean_menu_typo_spacing_unit":"","ocean_menu_link_color":"","ocean_menu_link_color_hover":"","ocean_menu_link_color_active":"","ocean_menu_link_background":"","ocean_menu_link_hover_background":"","ocean_menu_link_active_background":"","ocean_menu_social_links_bg":"","ocean_menu_social_hover_links_bg":"","ocean_menu_social_links_color":"","ocean_menu_social_hover_links_color":"","ocean_disable_title":"default","ocean_disable_heading":"default","ocean_post_title":"","ocean_post_subheading":"","ocean_post_title_style":"","ocean_post_title_background_color":"","ocean_post_title_background":0,"ocean_post_title_bg_image_position":"","ocean_post_title_bg_image_attachment":"","ocean_post_title_bg_image_repeat":"","ocean_post_title_bg_image_size":"","ocean_post_title_height":0,"ocean_post_title_bg_overlay":0.5,"ocean_post_title_bg_overlay_color":"","ocean_disable_breadcrumbs":"default","ocean_breadcrumbs_color":"","ocean_breadcrumbs_separator_color":"","ocean_breadcrumbs_links_color":"","ocean_breadcrumbs_links_hover_color":"","ocean_display_footer_widgets":"default","ocean_display_footer_bottom":"default","ocean_custom_footer_template":"0","footnotes":""},"class_list":["post-479","page","type-page","status-publish","hentry","entry"],"uagb_featured_image_src":{"full":false,"thumbnail":false,"medium":false,"medium_large":false,"large":false,"1536x1536":false,"2048x2048":false,"ocean-thumb-m":false,"ocean-thumb-ml":false,"ocean-thumb-l":false},"uagb_author_info":{"display_name":"Bryan Higgs","author_link":"https:\/\/bhiggs.x10hosting.com\/PracticalJavaProgramming\/author\/bryan\/"},"uagb_comment_info":0,"uagb_excerpt":"Final\u00a0classes: Preventing Inheritance Sometimes, you will wish to prevent someone from deriving a class from one of your classes. A class that cannot be used as a superclass is called a&nbsp;final class. 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