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POWhy am I getting a class cast exception if I have implemented comparator?
 

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  1. POWhy am I getting a class cast exception if I have implemented comparator?
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    <p>Please have a look at this:</p> <p>I have a sortedset:</p> <pre><code>SortedSet&lt;Individual&gt; individualSortedSet = new TreeSet&lt;Individual&gt;(new FitnessComparator()); </code></pre> <p>This is the comparator:</p> <pre><code>import java.util.Comparator; public class FitnessComparator implements Comparator&lt;Individual&gt; { @Override public int compare(Individual individual1, Individual individual2) { if (individual1.getFitness() == individual2.getFitness()) return 0; return (individual1.getFitness() &gt; individual2.getFitness())? 1 : -1; } } </code></pre> <p>The Individual class is just a data class.</p> <p>When I try to add ad element to the sortedset:</p> <pre><code>individualSortedSet.add(individual); </code></pre> <p>I get the following runtime error:</p> <pre><code>Exception in thread "main" java.lang.ClassCastException: Individual cannot be cast to java.lang.Comparable </code></pre> <p>I really dont understand why. I have looked at the following links but I cannot make it work..</p> <p><a href="https://stackoverflow.com/questions/12001946/why-im-not-getting-a-class-cast-exception-or-some-thing-else-when-adding-elemen">Why I&#39;m not getting a class cast exception or some thing else when adding element to TreeSet</a></p> <p><a href="https://stackoverflow.com/questions/2504803/list-to-treeset-conversion-produces-java-lang-classcastexception-myclass-cann">List to TreeSet conversion produces: &quot;java.lang.ClassCastException: MyClass cannot be cast to java.lang.Comparable&quot;</a></p>
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    1. USRegUser
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    1. COWhich line are you getting the exception from?
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      1. POWhy am I getting a class cast exception if I have implemented comparator?
      1. USKayaman
    2. CO@Kayaman according to his question - in `individualSortedSet.add(individual);`
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      1. POWhy am I getting a class cast exception if I have implemented comparator?
      1. USBenjamin Gruenbaum
    3. COBy any chance, do you have some other `Individual` class getting mixed up here?
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      1. POWhy am I getting a class cast exception if I have implemented comparator?
      1. USRohit Jain
 

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