Difference Betwixt Hashset Too Treeset Inwards Java

Difference betwixt HashSet together with TreeSet inwards Java

There are several differences betwixt an HashSet and a TreeSet is similar to what nosotros discussed equally a departure betwixt TreeMap together with HashMap. Anyway, Set together with Map are ii completely dissimilar interfaces therefore nosotros volition revisit those differences here. Probably the most of import departure between HashSet and TreeSet is the performance. HashSet is faster than TreeSet which agency if yous ask surgical operation utilization HashSet precisely HashSet doesn't furnish whatever variety of ordering therefore if yous ask ordering together with then yous ask to switch to TreeSet which provides sorting of keys. Sorting tin hold upwards natural order defined by a Comparable interface or whatever especial lodge defined past times Comparator interface inwards Java.

Apart from differences betwixt HashSet together with TreeSet, in that place are to a greater extent than or less mutual things betwixt them. let's run across what is mutual betwixt HashSet together with TreeSet inwards Java. By the way, this is i of the popular Java collection interview questions much similar ArrayList vs Vector together with Hashtable vs HashMap. If yous are going for whatever Java programming interview, it's worth preparing.

What is Common inwards HashSet together with TreeSet inwards Java

As I said in that place are lot of things which are mutual betwixt HashSet together with TreeSet inwards Java, let’s accept a look:

1)Both HashSet together with TreeSet implements java.util.Set interface which agency they follow contract of Set interface together with doesn't allow whatever duplicates.

2)Both HashSet together with TreeSet are non thread-safe together with non synchronized. Though yous tin brand them synchronized past times using Collections.synchronizedSet() method.

3) The tertiary similarity betwixt TreeSet together with HashSet is that Iterator of both classes is fail-fast in nature. They volition throw ConcurrentModificationException if Iterator is modified i time Iterator is created. this is non guaranteed together with application code should non rely on this code precisely Java makes best essay to neglect equally shortly equally it detects a structural modify inwards underlying Set.

HashSet vs TreeSet inwards Java

Now let's run across a pair of differences betwixt HashSet vs TreeSet inwards Java. This is plenty to determine whether yous should utilization HashSet or TreeSet inwards a given scenario.

1) The offset major departure betwixt HashSet together with TreeSet is performance. HashSet is faster than TreeSet together with should hold upwards preferred alternative if sorting of elements is non required. TreeSet is internally backed past times a Red-Black tree. For a detailed description of Red-Black Tree, yous should read a proficient mass on information construction together with algorithms e.g. Introduction to Algorithms past times Thomas Corman.

The surgical operation departure comes from the underlying information construction used past times TreeSet together with HashSet i.e. a tree together with a hash table. Adding an chemical component of a tree is slower than adding it to a hash tabular array precisely it is yet much faster than adding it into the right house inwards the linked listing or array. If the tree contains n elements, together with then an average log2N comparisons are required to expose the right seat for a novel element. For example, if the tree contains grand elements than adding a novel chemical component requires nearly 10 comparisons.

2) Second departure betwixt HashSet together with TreeSet is that HashSet allows nothing object precisely TreeSet doesn't allow nothing Object together with throw NullPointerException, Why, because TreeSet uses compareTo() method to compare keys together with compareTo() volition throw java.lang.NullPointerException equally shown inwards below instance :

HashSet<String> hashSet = new HashSet<String>();
hashSet.add("Java");
hashSet.add(null);
       
TreeSet<String> treeSet = new TreeSet<String>();
treeSet.add("C++");
treeSet.add(null); //Java.lang.NullPointerException
Output:
Exception inwards thread "main" java.lang.NullPointerException
        at java.util.TreeMap.put(TreeMap.java:541)
        at java.util.TreeSet.add(TreeSet.java:238)
        at test.CollectionTest.main(CollectionTest.java:27)
Java Result: 1

3) Another meaning departure betwixt HashSet together with TreeSet is that HashSet is backed past times HashMap piece TreeSet is backed by TreeMap inwards Java.

4) One to a greater extent than departure betwixt HashSet together with TreeSet which is worth remembering is that HashSet uses equals() method to compare ii objects inwards Set together with for detecting duplicates piece TreeSet uses compareTo() method for the same purpose. if equals() together with compareTo() are non consistent, i.e. for ii equal object equals should render truthful piece compareTo() should render null together with then it volition interruption the contract of Set interface together with volition allow duplicates inwards Set implementations similar TreeSet

5) Now the most of import departure betwixt HashSet together with TreeSet is ordering. HashSet doesn't guarantee whatever lodge piece TreeSet maintains objects inwards the Sorted lodge defined past times either Comparable or Comparator method inwards Java.

Here is a prissy summary slide of substitution differences betwixt TreeSet together with HashSet inwards Java, which compares both of these collections on ordering, sorting, performance, underlying information structure, the method used for duplicate detection together with how they are implemented inwards JDK.

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