which interface does hashmap implement in java
package MyPackage; import java.util.*; class HashMapExample { public static void main(String[] args) { Map< String, Integer> courses = new HashMap< String,Integer>(); // Add some courses. courses.put("Java Courses", new Integer(6)); courses.put("Cloud Courses", new Integer(7)); courses.put("Programming Courses", new Integer(5)); courses.put("Data Science Courses", new Integer(2)); System.out.println("Total courses: " + courses.size()); Set< Map.Entry< String,Integer> > st = courses.entrySet(); for (Map.Entry< String,Integer> me :st) { System.out.print(me.getKey()+":"); System.out.println(me.getValue()); } System.out.println(); String searchKey = "Java Courses"; if (courses.containsKey(searchKey)) System.out.println("Found total " + courses.get(searchKey) + " " + searchKey); } }