Java tutorial
import java.util.Map; import java.util.WeakHashMap; public class Main { public static void main(String[] args) { WeakHashMap<String, String> weakHashMap = new WeakHashMap<String, String>(); weakHashMap.put("1", "first"); weakHashMap.put("2", "two"); weakHashMap.put("3", "from java2s.com"); // print the contents System.out.println("Contents in the Map"); System.out.println(weakHashMap); // call clear() method System.out.println("Clear the Map"); weakHashMap.clear(); // again print the contents System.out.println("Contents in the Map"); System.out.println(weakHashMap); } }