Java Set

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The set extends the Collection interface and is included in Java.util package. It is an unordered collection of objects that cannot store duplicate values. It is a mathematical set implementation interface. This interface inherits the Collection interface's methods and adds a feature preventing identical elements' insertion. SortedSet and NavigableSet are two interfaces that expand the set implementation.

  • The navigable set interface extends the sorted set interface in the illustration above. 
  • Because a set does not keep its insertion order, the navigable set interface provides an implementation for traversing the Set. 
  • The navigable Set is implemented by a TreeSet, which implements a self-balancing tree. As a result, this interface allows us to traverse across this tree.


package week1.day2;
import java.util.LinkedHashSet;
import java.util.Set;
public class Calculator {
    public static void main(String[] args) {
        Set<String> showName = new LinkedHashSet<String>();
  • Here is an example of a Set.
  • We created a linked HashSet using a set.


[One, Piece]

Set Interface Operation

We can do all basic mathematical operations on the Set, such as intersection, union, and difference.

Consider the following two sets: set1 = [2,5,3,7,8] and set2 = [2,7,4,9,1]. On the Set, we can do the subsequent operation:

  • Intersection: The intersection operation returns all elements that appear in both sets. Set1 and set2 will intersect at [2,7].
  • Union: The union operation returns all elements of sets 1 and 2 in a single set, which can be set1 or set2. The sum of sets 1 and 2 is [1,2,3,4,5,7,8,9].
  • Difference: The difference operation removes any values present in another set from the set. The difference between sets 1 and 2 is [5,3,8,4,9,1].