What is TreeSet collection in java (class hierarchy & example)
Yogesh
1. What is TreeSet colletion in java ?
Elements in TreeSet are ordered using natural order or Comparator provided.
e.g. TreeSet containing integers will be sorted in natural order
e.g TreeSet containing user defined objects will be sorted using comparator supplied.
TreeSet is a NavigableSet implementation based on a TreeMap.
TreeSet is red black tree based implementation.
TreeSet is Red black tree implementation.
TreeSet provides guaranteed log(n) cost for the basic operations (add, remove & contains).
TreeSet contains unique element like HashSet.
null elements are not allowed in TreeSet.
TreeSet is not thread safe like HashSet, LinkedHashSet, EnumSet etc.
Iterator of TreeSet is fail-fast.
Iterator will throw ConcurrentModificationException, if TreeSet modified at any time after the iterator is created, in any way except through the iterator’s own remove method.
2. TreeSet collection class hierarchy:
3. Program – TreeSet collection of integers & characters in java (example)
package org.learn.collection.set.tset;
import java.util.Set;
import java.util.TreeSet;
public class DemoTreeSet {
public static void main(String[] args) {
Set<Integer> natualOrderNumber = new TreeSet<>();
natualOrderNumber.add(100);
natualOrderNumber.add(50);
natualOrderNumber.add(40);
natualOrderNumber.add(200);
natualOrderNumber.add(10);
System.out.println("1. Natual order integers in TreeSet: \n"+ natualOrderNumber);
Set<Character> natualOrderCharacter = new TreeSet<>();
natualOrderCharacter.add('J');
natualOrderCharacter.add('A');
natualOrderCharacter.add('V');
natualOrderCharacter.add('A');
System.out.println("2. Natual order characters in TreeSet: \n"+ natualOrderCharacter);
}
}
4. Output – TreeSet collection of integers & characters in java (example)
1. Natual order integers in TreeSet:
[10, 40, 50, 100, 200]
2. Natual order characters in TreeSet:
[A, J, V]