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Treeset Cannot Be


Another solution is compare on class names first, toString() values later. super T, ? Thanks in advnace . The returned set will throw an IllegalArgumentException on an attempt to insert an element outside its range. Source

Sign in to comment Contact GitHub API Training Shop Blog About © 2016 GitHub, Inc. With a custom Comparator you can still do it, but it's going to be harder. See my answer. –NPE Apr 11 '13 at 7:38 add a comment| up vote 1 down vote TreeSet requires for elements to implement Comparable if a custom Comparator is not set. If multiple threads access a tree set concurrently, and at least one of the threads modifies the set, it must be synchronized externally. http://stackoverflow.com/questions/15943031/why-does-treeset-throws-classcastexception

Cannot Be Cast To Java.lang.comparable Treemap

I cannot reproduce the problem with Java collections because there is no default collector that creates a SortedSet: java.util.SortedSet sortedSet = new TreeSet<>(); sortedSet.add("a"); sortedSet.add("b"); sortedSet .stream() .flatMap(s -> Arrays.asList(s.hashCode()).stream()) .collect(Collectors.toSet()); 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). I'm afraid I find free time to fix them in a short > time.

  1. How can I claim compensation?
  2. This will first operate on a Comparator that 1.
  3. share|improve this answer edited Mar 2 '14 at 4:18 answered Mar 2 '14 at 4:12 Erwin Bolwidt 12.7k92436 Erwin, I appreciate you taking your time for that thorough answer.
  4. Specified by: isEmptyin interfaceCollection<E> Specified by: isEmptyin interfaceSet<E> Overrides: isEmptyin

Your class does not. super E>comparator() Description copied from interface:SortedSet Returns the comparator used to order the elements in this set, or null if this set uses the natural ordering of its elements. If the API docs makes it clear how it works, with an additional example (downcasting to a Set and calling flatMap), this sounds like a reasonable solution. Treeset Comparator Question is if the scenario you described is mandatory then why compiler compiles that program. –Rais Alam Apr 11 '13 at 7:44 @FireFly: It's mandatory, but is not enforced

You get a ClassCastException when TreeMap tries to cast the key to a Comparable reference in order to use its compareTo method. Treeset Comparable Example Laythe Chamse Greenhorn Posts: 15 posted 7 years ago Hello EveryOne At JavaRanch I have a problem with my code, why do i get this Error: Exception in thread "main" java.lang.ClassCastException: Perhaps my story / rant is a bit over complex for this discussion. http://stackoverflow.com/questions/2504803/list-to-treeset-conversion-produces-java-lang-classcastexception-myclass-cann Can proliferate be applied to loyalty counters?

Even if parallel threads execute useNatural(), the returned value is defined in each case. Treeset Vs Hashset Ravi Kiran Va Ranch Hand Posts: 2234 I like... SCJP 1.4 - SCJP 6 - SCWCD 5 - OCEEJBD 6 - OCEJPAD 6 How To Ask Questions How To Answer Questions Laythe Chamse Greenhorn Posts: 15 posted 7 years Specified by: pollFirstin interfaceNavigableSet<E> Returns:the first element, or null if this set is emptySince: 1.6 pollLast publicEpollLast() Description copied from interface:

Treeset Comparable Example

up vote 0 down vote favorite So I'm trying to move all Strings of a certain length from a Collection of Strings (could either be a Set or a List) to Comparator vs. Cannot Be Cast To Java.lang.comparable Treemap extends T2, ? Cannot Be Cast To Java.lang.comparable Java This is best done at creation time, to prevent accidental unsynchronized access to the set: SortedSet s = Collections.synchronizedSortedSet(new TreeSet(...)); The iterators returned by this class's iterator method are fail-fast: if

Implementations may, but are not required to, throw this exception if fromElement cannot be compared to elements currently in the set. NullPointerException - if fromElement is null The RedBlackTree will contain at maximum 1 element then because it represents a Set and all elements are equal o_O. 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 Then it means that when you want to use a TreeSet for your Set implementation, then either you need to make all your code aware that it's a TreeSet so you Treeset Example

That's not a very good way of doing that - you can use the equals method in java.util.Date directly. Think about it for a moment. You need to download fresh complete dev builds to avoid untested combinations. have a peek here posted 7 years ago The compile error message says it all : MyOwnClass cannot be cast to java.lang.Comparable.

How is the correct air speed for fuel combustion obtained at the inlet of the combustor? Treeset Java If TreeSet / TreeMap could be changed completely, they should have no public constructors but factory methods instead (the constructors become private): public static However, the installation causing the latest stacktrace (comment #10) has not been updated for 2 months, so this also may be the cause for the mixture of old and new modules

Most outdated modules are disabled because of missing dependencies, so this shouldn't hurt. asked 2 years ago viewed 3793 times active 1 year ago Upcoming Events 2016 Community Moderator Election ends Nov 22 Linked 1 Why Map interface does not restrict key generic type Laythe Chamse Greenhorn Posts: 15 posted 7 years ago Jaydeep Vaishnav wrote:It seems that you are supposed to work with HashSet and not TreeSet. Java 8 Treeset super T, ?

John. The elements are ordered using their natural ordering, or by a Comparator provided at set creation time, depending on which constructor is used. and strphan for your valuable suggestions . Check This Out Christophe Verré Sheriff Posts: 14691 16 I like...

I'm not sure that it will ever be able to figure itself out, everything else, maybe. Just to give you a hint that think in terms of adding an object and you are good. With a custom Comparator you can still do it, but it's going to be harder. It is not only a smell, it is a *blocker for that solution.