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In order to sort Collection&lt;E&gt; its elemenst need to implemnet Comparable <br />
<br />
public static &lt;T extends Comparable&lt;? super T&gt;&gt; void sort(List&lt;T&gt; list)<br />
<br />
Bt you can aslo sort your own custom objects if you use<br />
another method whaich takes type implementing Comaprator as arguments:<br />
<br />
public static &lt;T&gt; void sort(List&lt;T&gt; list,<br />
&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; Comparator&lt;? super T&gt; c)
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Loook above they implemnent methods with different signatures
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Comparable takes one parameter and Comaparator takes two parameters
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<br />
see also here:<br />
<a href="http://stackoverflow.com/questions/1440134/java-what-is-the-difference-between-implementing-comparable-and-comparator" rel="ugc">http://stackoverflow.com/questions/1440134/java-what-is-the-difference-between-implementing-comparable-and-comparator</a>
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<br />
14 down vote accepted<br />
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<br />
<br />
The text below comes from <a href="http://lkamal.blogspot.com/2008/07/java-sorting-comparator-vs-comparable.html" rel="ugc">http://lkamal.blogspot.com/2008/07/java-sorting-comparator-vs-comparable.html</a><br />
<br />
Comparable<br />
<br />
A comparable object is capable of comparing itself with another object. The class itself must implements the java.lang.Comparable interface in order to be able to compare its instances.<br />
<br />
Comparator<br />
<br />
A comparator object is capable of comparing two different objects. The class is not comparing its instances, but some other class’s instances. This comparator class must implement the java.util.Comparator interface.<br />

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<br />
This is also nice explanation:<br />
<br />
Comparable lets a class implement its own comparison:<br />
<br />
&nbsp; &nbsp; it's in the same class (it is often an advantage)<br />
&nbsp; &nbsp; there can be only one implementation (so you can't use that if you want two different cases)<br />
<br />
By comparison, Comparator is an external comparison:<br />
<br />
&nbsp; &nbsp; it is typically in a unique instance (either in the same class or in another place)<br />
&nbsp; &nbsp; you name each implementation with the way you want to sort things<br />
&nbsp; &nbsp; you can provide comparators for classes that you do not control<br />
&nbsp; &nbsp; the implementation is usable even if the first object is null<br />

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I've requested that this question be closed as follows:<br />
<br />
Accepted answer: 0 points for stmani2005's comment <a href="http:/Q_27384931.html#37010218" rel="ugc">http:/Q_27384931.html#37010218</a><br />
<br />
for the following reason:<br />
<br />
helpful
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so why did you request to close this without allcatiing points?
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I believe this question was answered. Perhaps author just pressed the wrong button ?
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<br />
I'd suggest that the solution should be split between posting <a href="http:#36928865" rel="ugc">http:#36928865</a>&nbsp;which explains<br />
formal difference beween Comparable and Comparator in terms of method signatures<br />
and <a href="http:#36928886" rel="ugc">http:#36928886</a>&nbsp;which shows the difference between them in terms of most popular<br />
use cases.
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All,<br />
&nbsp; <br />
Following an 'Objection' by for_yan (at <a href="https://www.experts-exchange.com/questions/27409984/26-Oct-11-15-Automated-Request-for-Review-Objection-to-Accept-Q-27384931.html" rel="ugc nofollow">https://www.experts-exchange.com/questions/27409984/26-Oct-11-15-Automated-Request-for-Review-Objection-to-Accept-Q-27384931.html</a>) to the intended closure of this question, it has been reviewed by at least one Moderator and is being closed as recommended by the Expert.<br />
&nbsp;<br />
At this point I am going to re-start the auto-close procedure.<br />
&nbsp;<br />
Thank you,<br />
&nbsp;<br />
SouthMod<br />
Community Support Moderator
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<div class="content wysiwyg-content">
what is the difference between comparable and comparator interface
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what is the difference between comparable and comparator interface

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