Which class or interface serves as the base for implementing the Set collection in Java?

In Java, the basic interface for all Set collections is the java.util.Set interface. It defines the fundamental methods for working with sets, such as adding, removing, and checking for the presence of elements.

Example usage:

import java.util.Set;
import java.util.HashSet;

Set<String> set = new HashSet<>();
set.add("apple");
set.add("banana");
System.out.println(set.contains("apple")); // true

Thus, all implementations of sets (for example, HashSet, TreeSet, LinkedHashSet) implement the Set interface.