blocks|key|261350|text|它们被重写，以便可以被记录下来，以便指定与Collection接口中指定的约定相比，列表如何精炼这些方法的约定。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|261351|例如，文档中记录了List中的add()方法，以指定将元素添加到列表末尾。这不能在Collection中指定，因为Collection没有开始和结束。|offset|length|style|CODE|261352|entityMap^0|0|9|4|F|5|0^^$0|@$1|2|3|4|5|6|7|J|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|K|8|@$D|L|E|M|F|G]|$D|N|E|O|F|G]]|9|@]|A|$]]|$1|H|3|-4|5|6|7|P|8|@]|9|@]|A|$]]]|I|$]]

They're re-written so that they can be documented, in order to specify how the List refines the contract of these methods compared to the contract specified in the Collection interface.

For example, the <code>add()</code> method in <code>List</code> is documented to specify that the element is added to the end of the list. This can't be specified in Collection, since a Collection doesn't have a beginning and an end.

blocks|key|261376|text|JavaDoc和API契约会随着继承层次结构的下移而发生一些变化，或者变得更加具体。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|261377|List重新声明了这些方法，并为它们提供了更具体的JavaDoc。|261378|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|$]]

JavaDoc and API contracts change somewhat/ or become more specific, as you move down the inheritance heirarchy.

List re-declares these methods &amp; gives them more specific JavaDoc.

blocks|key|44701|text|toArray方法上的签名表明您是从编译后的.class文件中提取出来的。class+file+format指定.class文件不重复从超接口继承的方法，所以我怀疑您用来获取这些方法的工具显示的是一个复合视图；这些方法实际上并不存在于List上。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|44702|entityMap|0|LINK|mutability|MUTABLE|url|http://docs.oracle.com/javase/specs/jvms/se7/html/jvms-4.html^0|0|7|M|6|1K|6|39|4|11|H|0|0^^$0|@$1|2|3|4|5|6|7|N|8|@$9|O|A|P|B|C]|$9|Q|A|R|B|C]|$9|S|A|T|B|C]|$9|U|A|V|B|C]]|D|@$9|W|A|X|1|Y]]|E|$]]|$1|F|3|-4|5|6|7|Z|8|@]|D|@]|E|$]]]|G|$H|$5|I|J|K|E|$L|M]]]]

The signatures on the <code>toArray</code> methods suggest that you extracted this from the compiled <code>.class</code> files. The <a href="http://docs.oracle.com/javase/specs/jvms/se7/html/jvms-4.html" rel="nofollow">class file format</a> specifies that the <code>.class</code> file does not repeat methods inherited from superinterfaces, so I suspect that whatever tool you used to obtain these was showing you a composite view; the methods aren't actually physically present on <code>List</code>.

blocks|key|44736|text|Collection<T>只是一组项目。就其本身而言，除了持有对其成员的许多项的引用之外，它并没有更多的要求。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|44737|在基本的java+api中，有两种主要类型的集合：List<T>和Set<T>。|44738|List<T>有额外的要求来维护特定的顺序(插入顺序，排序顺序，...)它的所有项目。因此，如果您请求项目N，则列表将始终返回与N相同的项目。|44739|Set<T>对订单不作任何保证，但对商品的唯一性提供保证。一个项目A不能添加到集合中两次，或者在一个集合中只出现一次。|44740|你应该熟悉“标记”接口的实践。Serializable就是其中之一，并且通常是谈论这一点时的基本示例。而List<T>和Set<T>就是这样声明的，它们将集合标记为一个或另一个，以便通知程序员它们可以从收到的集合中预期的行为。|44741|请参考"Effective“的第37项(第6章)，了解如何比使用注释更好地解释这一点。|44742|还有一个事实是，myCollection+instanceof+MyInterface比myCollection.getClass().isAnnotationPresent(MyAnnotation.class)或myCollection.getClass().getAnnotation(MyAnnotation.class)+!=+null更快。|44743|entityMap^0|0|D|0|P|7|X|6|0|0|7|0|0|6|0|F|C|1G|7|1O|6|0|0|8|Z|18|1R|30|1T|0^^$0|@$1|2|3|4|5|6|7|T|8|@$9|U|A|V|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|W|8|@$9|X|A|Y|B|C]|$9|Z|A|10|B|C]]|D|@]|E|$]]|$1|H|3|I|5|6|7|11|8|@$9|12|A|13|B|C]]|D|@]|E|$]]|$1|J|3|K|5|6|7|14|8|@$9|15|A|16|B|C]]|D|@]|E|$]]|$1|L|3|M|5|6|7|17|8|@$9|18|A|19|B|C]|$9|1A|A|1B|B|C]|$9|1C|A|1D|B|C]]|D|@]|E|$]]|$1|N|3|O|5|6|7|1E|8|@]|D|@]|E|$]]|$1|P|3|Q|5|6|7|1F|8|@$9|1G|A|1H|B|C]|$9|1I|A|1J|B|C]|$9|1K|A|1L|B|C]]|D|@]|E|$]]|$1|R|3|-4|5|6|7|1M|8|@]|D|@]|E|$]]]|S|$]]

<code>Collection&lt;T&gt;</code> is just a group of item.
In itself it doesn't have any more requirements than holding references to the many items that are its members.

In the basic java api there is two main types of collections: <code>List&lt;T&gt;</code> and <code>Set&lt;T&gt;</code>.

<code>List&lt;T&gt;</code> have the extra requirement to maintain a certain order (insertion order, sorted order, ...) for all its items. So that if you request item N the list will always return the same item for N.

<code>Set&lt;T&gt;</code> does not offer any guarantee on order but offers guarantee on uniqueness of the items. An item A cannot be added twice to a Set, or will appear only once in a set.

You should acquaint yourself with the practice of "marker" interface. <code>Serializable</code> is one of those, and generally the basic example when talking about this. And <code>List&lt;T&gt;</code> and <code>Set&lt;T&gt;</code> are declared as such, they mark a collection as one or the other in order to inform the programmer of the behaviour they can expect from the collection they receive.

Please refer to Item 37 (Chapter 6) of "Effective Java" for a very good explanation on how this is better than using annotations.

And there is also the fact that <code>myCollection instanceof MyInterface</code> is faster than <code>myCollection.getClass().isAnnotationPresent(MyAnnotation.class)</code> or <code>myCollection.getClass().getAnnotation(MyAnnotation.class) != null</code>.

blocks|key|44782|text|首先，List接口继承了所有的Collection方法，所以Collection接口中存在的所有方法也将存在于List接口中，但List接口中有额外的方法(请您自己查看)，这些方法描述了list的行为|type|unstyled|depth|inlineStyleRanges|entityRanges|data|44783|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|$]]

First of all interface List inherit all Collection methods,so all methods that exists in Collection interface will exists also in List interface,but List interface have extra methods,(check it by ur self) which describes the behavior of list

The Collection interface has multiple methods. The List interface extends the Collection interface. It declares the same methods as the Collection interface? Why is this so?

For example

<pre><code>interface Collection extends Iterable
{
 public abstract int size();
 public abstract boolean isEmpty();
 public abstract boolean contains(java.lang.Object);
 public abstract java.util.Iterator&lt;E&gt; iterator();
 public abstract java.lang.Object[] toArray();
 public abstract &lt;T extends java/lang/Object&gt; T[] toArray(T[]);
 public abstract boolean add(E);
 public abstract boolean remove(java.lang.Object);
 public abstract boolean containsAll(java.util.Collection&lt;?&gt;);
 public abstract boolean addAll(java.util.Collection&lt;? extends E&gt;);
 public abstract boolean removeAll(java.util.Collection&lt;?&gt;);
 public abstract boolean retainAll(java.util.Collection&lt;?&gt;);
 public abstract void clear();
 public abstract boolean equals(java.lang.Object);
 public abstract int hashCode();
}
</code></pre>

and same methods are also present in List interface:

<pre><code>public interface List extends Collection
{
 public abstract int size();
 public abstract boolean isEmpty();
 public abstract boolean contains(java.lang.Object);
 public abstract java.util.Iterator&lt;E&gt; iterator();
 public abstract java.lang.Object[] toArray();
 public abstract &lt;T extends java/lang/Object&gt; T[] toArray(T[]);
 public abstract boolean add(E);
 public abstract boolean remove(java.lang.Object);
 public abstract boolean containsAll(java.util.Collection&lt;?&gt;);
 public abstract boolean addAll(java.util.Collection&lt;? extends E&gt;);
 public abstract boolean removeAll(java.util.Collection&lt;?&gt;);
 public abstract boolean retainAll(java.util.Collection&lt;?&gt;);
 public abstract void clear();
 public abstract boolean equals(java.lang.Object);
 public abstract int hashCode();
}
</code></pre>

Is it a requirement to write these methods again in List if it is already extending the Collection interface?

Why does List interface extend Collection interface?

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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Collection接口有多个方法。List接口扩展了Collection接口。它声明了与Collection接口相同的方法？为何会这样呢？例如interface Collection extends Iterable{     public abstract int size(); public abstract b...

问为什么列表接口要扩展收款接口？
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