blocks|key|4495445|text|这是一个Java的design+decision。你永远不会得到它，所以不要太担心它。尽管MI可能会帮助您制作Mixins，但这是唯一好的MI。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|4495446|entityMap|0|LINK|mutability|MUTABLE|url|http://www.javaworld.com/javaqa/2002-07/02-qa-0719-multinheritance.html^0|9|F|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

It was a <a href="http://www.javaworld.com/javaqa/2002-07/02-qa-0719-multinheritance.html" rel="noreferrer">design decision</a> of Java. You'll never get it, so don't worry too much about it. Although MI might help you make Mixins, that's the only good MI will ever do you.

blocks|key|1504698|text|我读到过大多数程序员没有以适当的方式使用多重继承。在多重继承的情况下，“只是为了重用代码而继承类”不是最佳实践。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1504699|在大多数情况下，许多程序员不知道何时使用简单继承。多重继承必须谨慎使用，而且只有当你知道自己在做什么的时候，才能有一个好的设计。|1504700|我不认为java+(如c%2B%2B)中的多重继承的缺失会给你的代码/应用程序设计/问题域映射到类带来限制。|1504701|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|H|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|I|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|J|8|@]|9|@]|A|$]]|$1|F|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|G|$]]

I have read that most programmers don't use multiple inheritance in a proper way. "Just go ahead and inherit from a class just to reuse code" is not the best practice in case of multiple inheritance. 

Many programmers do not know when to use simple inheritance in most cases. Multiple inheritance must be used with caution and only if you know what you are doing if you want to have a good design.

I don't think that the lack of multiple inheritance in java (as in c++) will put restrictions in your code / application design / problem domain mapping into classes.

blocks|key|1504777|text|简单性。引用Tom+Sintes的话：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1504778|1504779|+Java设计团队努力使Java：|blockquote|1504780|1504781|1504782|1504783|简单、面向对象且熟悉的|unordered-list-item|1504784|强大而安全的|1504785|体系结构中立且便携的|1504786|高性能线程化和动态|1504787|1504788|省略Java语言的多重继承的原因主要源于“简单、面向对象和熟悉”的目标。作为一种简单的语言，Java的创建者想要一种大多数开发人员无需大量培训就能掌握的语言。为此，他们努力使该语言尽可能地类似于C%2B%2B+(熟悉)，而不带着C%2B%2B不必要的复杂性(简单)。|1504789|在设计者看来，多重继承带来的问题和混乱比它解决的问题更多。因此，他们减少了语言的多重继承(就像他们减少了操作符重载一样)。设计师们丰富的C%2B%2B经验告诉他们，多重继承是不值得头疼的。|1504790|entityMap|0|LINK|mutability|MUTABLE|url|http://www.javaworld.com/javaqa/2002-07/02-qa-0719-multinheritance.html^0|6|A|0|0|0|0|0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|16|8|@]|9|@$A|17|B|18|1|19]]|C|$]]|$1|D|3|-4|5|6|7|1A|8|@]|9|@]|C|$]]|$1|E|3|F|5|G|7|1B|8|@]|9|@]|C|$]]|$1|H|3|-4|5|6|7|1C|8|@]|9|@]|C|$]]|$1|I|3|-4|5|6|7|1D|8|@]|9|@]|C|$]]|$1|J|3|-4|5|6|7|1E|8|@]|9|@]|C|$]]|$1|K|3|L|5|M|7|1F|8|@]|9|@]|C|$]]|$1|N|3|O|5|M|7|1G|8|@]|9|@]|C|$]]|$1|P|3|Q|5|M|7|1H|8|@]|9|@]|C|$]]|$1|R|3|S|5|M|7|1I|8|@]|9|@]|C|$]]|$1|T|3|-4|5|6|7|1J|8|@]|9|@]|C|$]]|$1|U|3|V|5|6|7|1K|8|@]|9|@]|C|$]]|$1|W|3|X|5|6|7|1L|8|@]|9|@]|C|$]]|$1|Y|3|-4|5|6|7|1M|8|@]|9|@]|C|$]]]|Z|$10|$5|11|12|13|C|$14|15]]]]

Simplicity. To quote <a href="http://www.javaworld.com/javaqa/2002-07/02-qa-0719-multinheritance.html" rel="nofollow">Tom Sintes</a>,

<blockquote>
 The Java design team strove to make Java:
 
 <ul>
 <li>Simple, object oriented, and familiar </li>
 <li>Robust and secure </li>
 <li>Architecture neutral and portable </li>
 <li>High performance </li>
 <li>Interpreted, threaded, and dynamic</li>
 </ul>
 
 The reasons for omitting multiple inheritance from the Java language
 mostly stem from the "simple, object oriented, and familiar" goal. As
 a simple language, Java's creators wanted a language that most
 developers could grasp without extensive training. To that end, they
 worked to make the language as similar to C++ as possible (familiar)
 without carrying over C++'s unnecessary complexity (simple).
 
 In the designers' opinion, multiple inheritance causes more problems
 and confusion than it solves. So they cut multiple inheritance from
 the language (just as they cut operator overloading). The designers'
 extensive C++ experience taught them that multiple inheritance just
 wasn't worth the headache.
</blockquote>

blocks|key|203235|text|如果java支持多重继承，那么它可能会影响java其他特性|type|unstyled|depth|inlineStyleRanges|entityRanges|data|203236|考虑到用于调用超类的constructor.if+()方法具有多个超类(由于多重继承)，那么编译器会对应该调用哪个超类构造函数感到困惑并抛出错误|203237|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|F|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|G|8|@]|9|@]|A|$]]|$1|D|3|-4|5|6|7|H|8|@]|9|@]|A|$]]]|E|$]]

if java support multiple inheritance then it may effect other features of java 
consider super() method which is used to call super class constructor.if program has multiple super class(because of multiple inheritance) then compiler will get confused about which super class constructor should be called and throw an error

blocks|key|203220|text|Java的设计者们决定。多重继承可以通过使用接口来模拟。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|203221|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

Java designers decided that. Multiple inheritance can be simulated by the use of interfaces.

blocks|key|1279113|text|一个简单的答案是，java.lang.Object中的所有类都是从Java派生的。所以，你会一直有一个菱形的问题....:-D|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1279114|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

One simple answer is that all classes in Java derive from java.lang.Object IIRC. So, you would always have a diamond problem... :-D

blocks|key|203241|text|Java确实没有用来支持实现的多重继承(只支持类型，即接口)。这是一个设计上的决定。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|203242|然而，从Java+8开始，它支持使用默认方法的多重继承。请参阅http://docs.oracle.com/javase/tutorial/java/IandI/multipleinheritance.html|offset|length|203243|203244|实现的多重继承是从多个类继承方法定义的能力。这种类型的多重继承会出现问题，例如名称冲突和多义性。..。默认方法引入了一种实现的多重继承形式。|blockquote|203245|203246|entityMap|0|LINK|mutability|MUTABLE|url|http://docs.oracle.com/javase/tutorial/java/IandI/multipleinheritance.html^0|0|V|22|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|T|8|@]|9|@$D|U|E|V|1|W]]|A|$]]|$1|F|3|-4|5|6|7|X|8|@]|9|@]|A|$]]|$1|G|3|H|5|I|7|Y|8|@]|9|@]|A|$]]|$1|J|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]|$1|K|3|-4|5|6|7|10|8|@]|9|@]|A|$]]]|L|$M|$5|N|O|P|A|$Q|R]]]]

It is true that Java did not use to support multiple inheritance of implementation (just of type i.e. interface). That was a design decision.

However, since Java 8, it supports multiple inheritance using default methods. See <a href="http://docs.oracle.com/javase/tutorial/java/IandI/multipleinheritance.html" rel="nofollow">http://docs.oracle.com/javase/tutorial/java/IandI/multipleinheritance.html</a>:

<blockquote>
 Multiple inheritance of implementation is the ability to inherit
 method definitions from multiple classes. Problems arise with this
 type of multiple inheritance, such as name conflicts and ambiguity.
 ... Default methods introduce one form of multiple inheritance of
 implementation.
</blockquote>

blocks|key|1503144|text|当多个父类定义了它们自己的实现时，菱形问题就出现了，而这两个类的子类必须处理要使用哪个实现的模糊性。那么，如果Java中的所有类都派生自Object，那又如何呢？“单父类，多个派生类”与“多个父类，单个派生类”不同|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1503145|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

The diamond problem arises when multiple parent classes define their own implementations of something and the child class of these two has to deal with the ambiguity of which implementation to use. So what if all classes in Java derive from Object, that's a single parent class. "Single parent, multiple derived classes" is not the same as "Multiple parents, single derived class"

Java is not allowing inheritance from multiple classes (still it allows inheritance from multiple interfaces.), I know it is very much inline with classic diamond problem. But my questions is why java is not allowing multiple inheritance like C++ when there is no ambiguity (and hence no chances of diamond problem) while inheriting from multiple base class ?

Multiple Inheritance in java

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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Java不允许从多个类继承(仍然允许从多个接口继承)，我知道这非常符合经典的菱形问题。但我的问题是，当从多个基类继承时没有歧义(因此没有菱形问题的机会)时，为什么java不允许像C++那样的多重继承？

问java中的多重继承
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