Iterate/loop elements/string objects of HashSet collection in java8 (example)

  1. HashSet class implements the Set interface, backed by a hash table.
  2. HashSet contains the unique elements.
    • HashSet does not contains any duplicate keys
    • HashSet can have only 1 null key.
  3. HashSet does not maintained the order of elements or keys.
  4. HashSet is UnSynchronized and not thread safe.
  5. Given a HashSet collection having String objects in java.
    • We would like to iterate or loop through HashSet collection using java 8.

1. Methods to traverse or loop HashSet collection in java.

  1. Traverse HashSet<String> using Iterator.
  2. Iterate HashSet<String> using Java 8 forEach.

2. Iterate or loop String objects of HashSet collection (java8/example)

package org.learn.collection.set.hset;
 
import java.util.HashSet;
import java.util.Iterator;
import java.util.Set;
 
public class DemoIterationHashSet {
 
    public static void main(String[] args) {
        Set<String> setSports = new HashSet<>();
        setSports.add("Tennis");
        setSports.add("Cricket");
        setSports.add("Tennis");
        setSports.add(null);
        setSports.add("Basketball");
        setSports.add("Cricket");
        setSports.add(null);
        setSports.add("Basketball");
        setSports.add("Golf");
        setSports.add("Boxer");
 
        System.out.println("Method 1 - Iterate HashSet: ");
        demoIterateHashSet(setSports);
 
        System.out.println("\nMethod 2 - Iterate HashSet using java 8: ");
        demoIterateHashSetJava8(setSports);
    }
 
    private static void demoIterateHashSet(Set<String> setSports) {
        Iterator<String> iterator = setSports.iterator();
        while (iterator.hasNext()) {
            System.out.println(iterator.next());
        }
    }
 
    private static void demoIterateHashSetJava8(Set<String> setSports) {
        setSports.forEach((key) -> {
            System.out.println(key);
        });
    }
}

3. Output :Iterate/loop String objects of HashSet collection (java8/example)

Method 1 - Iterate HashSet:
null
Tennis
Cricket
Golf
Basketball
Boxer
 
Method 2 - Iterate HashSet using java 8:
null
Tennis
Cricket
Golf
Basketball
Boxer