HashSet removeAll() method in java
example on removeAll() method for NullPointerException import java.util.HashSet; public class HashSetRemoveAllMethodExample { public static void main(String[] args) { try { HashSet<Integer> hs1 = new HashSet<Integer>(); hs1.add(2); hs1.add(4); hs1.add(6); hs1.add(8); hs1.add(10); // printing hs1 System.out.println("HashSet before using removeAll() method: " + hs1); // create another object of HashSet HashSet<Integer> hs2 = null; // printing hs2 System.out.println("Elements to be removed: " + hs2); System.out.println("Trying to pass null: "); // removing elements from HashSet // specified in hs2 using removeAll() method hs1.removeAll(hs2); System.out.println("HashSet after using removeAll() method: " + hs1); } catch(NullPointerException ex) { System.out.println("Exception: " + ex); } } }
