There are following two ways to iterate through HashSet:
1) Using Iterator
2) Without using Iterator
Example 1: Using Iterator
import java.util.HashSet;
import java.util.Iterator;
class IterateHashSet{
public static void main(String[] args) {
// Create a HashSet
HashSet<String> hset = new HashSet<String>();
//add elements to HashSet
hset.add("Chaitanya");
hset.add("Rahul");
hset.add("Tim");
hset.add("Rick");
hset.add("Harry");
Iterator<String> it = hset.iterator();
while(it.hasNext()){
System.out.println(it.next());
}
}
}
Output:
Chaitanya Rick Harry Rahul Tim
Example 2: Iterate without using Iterator
import java.util.HashSet;
import java.util.Set;
class IterateHashSet{
public static void main(String[] args) {
// Create a HashSet
Set<String> hset = new HashSet<String>();
//add elements to HashSet
hset.add("Chaitanya");
hset.add("Rahul");
hset.add("Tim");
hset.add("Rick");
hset.add("Harry");
for (String temp : hset) {
System.out.println(temp);
}
}
}
Output:
Chaitanya Rick Harry Rahul Tim
Hello!
Can I ask you a question?
Is there any difference in declarations in 1st and 2nd examples:
HashSet hset = new HashSet(); and
Set hset = new HashSet();
Technically, yes, for the 1st line, you are coding to an implementation while for the 2nd line, you are coding to an interface. In otherwords, hashset is a concrete class while the Seet is an interface
It is always a good idea to put the interface name on the left side from good software engineering practices. It hides implementation details.