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Cannot Be Cast To Java.lang.comparable Treeset

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one that does not throw unexpectedly at runtime. You may want to use a HashSet instead, which have its own contracts. There's no way around it. –user2357112 Feb 6 '14 at 2:08 add a comment| 2 Answers 2 active oldest votes up vote 2 down vote accepted You'll notice the javadoc of How can I trust that this is google? Source

extends U> that); @Override SortedSet zipWith(Iterablehttp://stackoverflow.com/questions/15943031/why-does-treeset-throws-classcastexception

Treeset Comparable Example

If your objects can not be ordered one way or another, then a TreeSet wouldn't make sense. Comparators are shared between different persistent versions of a collection. checks if the value is instanceof Comparable 3.

Set s = new TreeSet(); s.add(new Employee(1001)); Or Set s = new HashSet(); s.add(new Employee(1001)); s.add(new Employee(1002)); Then result is success there is no exception. more stack exchange communities company blog Stack Exchange Inbox Reputation and Badges sign up log in tour help Tour Start here for a quick overview of the site Help Center Detailed comparison is always 0, is not a good idea in a Set. Java Treeset Example However, it is still unsafe.

I'm not sure how people in general deal with this kind of issue, and I know that flatMap() is coming from the Traversable trait, but somehow it would be great if Cannot Be Cast To Java.lang.comparable Treemap extends U> mapper); The above are Set methods. I agree that it is a tough decision to break the API by returning a Set instead of a SortedSet. http://stackoverflow.com/questions/2504803/list-to-treeset-conversion-produces-java-lang-classcastexception-myclass-cann I changed one method signature and broke 25,000 other classes.

The RedBlackTree will contain at maximum 1 element then because it represents a Set and all elements are equal o_O. Arraylist Is Ordered While Hashset Is Not Is adding the ‘tbl’ prefix to table names really a problem? The added object cannot be compared with the elements currently in the set, the add(Object) call throws a ClassCastException. Lastly, I don't think it's been said here, but this same issue probably applies to .map as well.

Cannot Be Cast To Java.lang.comparable Treemap

How to harness Jupiter's gravitational energy? SortedSet / SortedMap are interfaces. Treeset Comparable Example TreeSet and TreeMap use sorting for their internal storage. Implement Comparable Also we can't take the naturalComparator by default and fall back to the unordered comparator because we would have internally to catch a ClassCastException which takes too much time.

Wouter Oet Saloon Keeper Posts: 2700 I like... this contact form Why didn’t Japan attack the West Coast of the United States during World War II? Thank you. The sorted set is unable to call the second Employee element's compareTo() method. How Treeset Works Internally In Java

Anyone know what it is? I will come back to this issue during this week (because of too many parallel tasks already). - Daniel JΛVΛSLΛNG member danieldietrich commented Sep 28, 2016 • edited I agree that For a better animation of the solution from NDSolve How can I check that the voltage output from this voltage divider is 2.25V? have a peek here How can I check that the voltage output from this voltage divider is 2.25V?

TreeSet.empty() et al, could still use the naturalComparator. Comparable Example In Java The scan methods look like this: // DEV-NOTE: The return type is either Set or SortedSet, depending whether U is Comparable @Override Set scanLeft(U zero, BiFunctionTreeSet is an example of a sorted set.

Is it unethical to poorly translate an exam from Dutch to English and then present it to the English speaking students? To make an object comparable, user-defined class must implement the Comparable interface. 2. extends U> operation); // DEV-NOTE: The return type is either Set or SortedSet, depending whether U is Comparable @Override Set scanRight(U zero, BiFunction

Ravi Kiran Va Ranch Hand Posts: 2234 I like... But if we do so, the whole hash(o1, o2) makes no sense any more. But this is not possible in the case of empty collections where we can't take an element to check if it is comparable. http://electrictricycle.net/cannot-be/cannot-be-cast-to-java-lang-comparable-set.html Comparator vs.

super E>> create(Collection

I think that is a good solution. Newton's second law for individual forces What commercial flight route requires the most (minimum possible) stops/layovers from A to B? Supposing an un-ordered Comparator was possible, would it be possible to tell when it should be used (as opposed to natural ordering) without attempting a Comparable cast? super T, ?

Why cast an A-lister for Groot? Java's int is 32 bit, our machines address 64 bit memory. In fact I do not plan to break anything in near future (opposed than stated in one of my previous blog posts). I'm using javaslang 2.0.1 version.

How would I call that in this code? –Mxt Feb 6 '14 at 2:11 @Mxt Comparator is an interface. What is the definition of "rare language"? JΛVΛSLΛNG member danieldietrich commented Oct 4, 2016 • edited There is still a problem (I already mentioned above: "Checking for hashCode collisions would be problematic."): hash(o1, o2) can be 0 for It can also occur when creating empty collections without specifying a Comparator.

Take a look at TreeMap.put(K key, V value) source codes and you'll clearly see the reasons behind all your questions (TreeSet is based on TreeMap, hence the source reference). extends T1, ? package test; import java.util.Arrays; import java.util.SortedSet; import java.util.TreeSet; import java.util.function.BiConsumer; import java.util.function.BinaryOperator; import java.util.function.Function; import java.util.function.Supplier; import java.util.stream.Collector; public class JavaSortedSetTest { public static void main(String[] args) { SortedSet sortedSet = Mysterious creeper-like explosions Does sputtering butter mean that water is present?