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A Java program to check if a set is a subset of another set

Java Examples Comprehensive

In this instance, we will learn how to check if one collection is a subset of another collection in Java.

To understand this example, you should understand the followingJava programmingTopic:

Example1: Use HashSet class to check the subset of Set

Example

import java.util.HashSet;
import java.util.Set;
class Main {
　　public static void main(String[] args) {
　　　　//Create the first collection
　　　　Set<Integer> numbers = new HashSet<>();
　　　　numbers.add(1);
　　　　numbers.add(2);
　　　　numbers.add(3);
　　　　numbers.add(4);
　　　　System.out.println("Numbers: ")　+　numbers);
　　　　//　Create the second collection
　　　　Set<Integer> primeNumbers = new HashSet<>();
　　　　primeNumbers.add(2);
　　　　primeNumbers.add(3);
　　　　System.out.println("Prime numbers: ")　+　primeNumbers);
　　　　//Check if primeNumbers is a subset of numbers
　　　　boolean result = numbers.containsAll(primeNumbers);
　　　　System.out.println("Is primeNumbers a subset of Numbers? ")　+　result);
　　}
}

Output Result

Numbers: [1,　2,　3,　4]
Prime numbers: [2,　3]
Is primeNumbers a subset of Numbers? true

In the above example, we created two collections named numbers and primeNumbers. We implemented this collection using HashSet class. Note this line,

numbers.containsAll(primeNumbers);

Here, we use the containsAll() method to check if primeNumbers is a subset of numbers.

Example2: Use TreeSet class to check the subset of the collection