Java “扩展对象”有目的还是多余？
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Does 'extends Object' have a purpose or is it redundant?
提问by Andrei Ciobanu
Following a tutorial on the internet regarding Soap development with Java, I found this link, with a rather unusual code for myself.
根据互联网上关于使用 Java 进行 Soap 开发的教程，我找到了这个链接，其中包含了一个相当不寻常的代码。
The code:
编码：
public class SoapService extends Object {
/** Creates new SoapService */
public SoapService() {
}
/** This is the SOAP exposes method
*/
public String sayGreeting(String name)
{
return "Hello "+name;
}
}
What's with the 'extends Object' syntax ? I've never encountered this kind of syntax (only on Generics).
“扩展对象”语法有什么用？我从未遇到过这种语法（仅在泛型上）。
Does this syntax has any purpose or is 'plain dumb' ?
这种语法有任何目的还是“愚蠢”？
采纳答案by Thomas L?tzer
Unless the Object class is not actually the java.lang.Objectclass (the tutorial does not include the imports, so it's hard to see), the extends Objectis redundant.
除非 Object 类实际上不是java.lang.Object类（教程不包括导入，因此很难看到），否则extends Object是多余的。
回答by Vanessa MacDougal
回答by Erich Douglass
All objects in Java implicitly extend Object, so I'd say it's redundant.
Java 中的所有对象都隐式扩展Object，所以我会说它是多余的。
回答by Trevor Tippins
All classes extend Object implicitlyanyway so it's just redundant coding having no impact.
无论如何，所有类都隐式地扩展了 Object ，因此它只是没有影响的冗余编码。
回答by Uri
No. It's just explicitly doing something that is implicit.
不，它只是明确地做一些隐含的事情。
回答by Kylar
It's unneeded. Every class in Java extends Object at some level. Leave it out, unless you need to clarify something specific.
这是不需要的。Java 中的每个类都在某种程度上扩展了 Object。除非你需要澄清一些具体的事情，否则不要管它。
回答by Martin Milan
My vote, plain dumb - but then I only play with Java...
我的投票，很愚蠢 - 但后来我只玩 Java ......
But any class inherits from the Object Class as far as I know...
但据我所知，任何类都继承自对象类......
回答by Yishai
It is legal but useless boilerplate. Everything extends Object so the language spec allows you to leave it out, and it generally should be left out (some writers of coding standards disagree).
这是合法但无用的样板。一切都扩展了 Object，因此语言规范允许您将其排除在外，并且通常应该将其排除在外（一些编码标准的作者不同意）。
The situation is the same in generics (extends Object is implicit and redundant), it is just that for some reason (I have seen some claim early buggy Generics implementations had issues with the ? wildcard) it has caught on a bit more there.
泛型中的情况是一样的（扩展 Object 是隐式和冗余的），只是由于某种原因（我看到一些声称早期有缺陷的泛型实现有 ? 通配符的问题）它在那里流行了一点。
回答by Lauri
Extends clause is optional as stated in Java Language Specification. If it is omitted, the class is derived from java.lang.Object. It is just a matter of coding style to write it or not to write it in this case. Usually it is omitted.
Extends 子句是可选的，如Java Language Specification 中所述。如果省略，则该类派生自 java.lang.Object。在这种情况下，编写或不编写它只是编码风格的问题。通常省略。
回答by mfx
Looks a bit like generated code - it's extra effort for a source code generator to omitthe "extends" clause if it is not needed, especially if the generator is template-based.
看起来有点像生成的代码 -如果不需要，源代码生成器省略“extends”子句是额外的努力，特别是如果生成器是基于模板的。
