The removeIf() method of Vector removes all of those elements from Vector which satisfies the condition passed as a parameter to this method. This method returns true if some element are removed from the Vector.
Java 8 has an important in-built functional interface which is Predicate. Predicate, or a condition checking function, which checks the given input for a given condition and returns a boolean result for the same indicating whether the condition was met or not.
Syntax:
public boolean removeIf(Predicate<? super E> filter)
Parameter: This method takes a parameter filter which represents a predicate which returns true for elements to be removed.
Returns: This method returns True if predicate returns true and some elements were removed.
Exception: This method throws NullPointerException if the specified filter is null.
Below programs illustrate removeIf() method of Vector:
Example 1: To demonstrate removeIf() method on vector which contains a set of Numbers and only the numbers which are divisible by 2 will be removed.
// Java Program Demonstrate removeIf()// method of Vector import java.util.*; public class GFG { public static void main(String[] args) { // create an Vector which going to // contains a list of Numbers Vector<Integer> Numbers = new Vector<Integer>(); // Add Number to list Numbers.add(22); Numbers.add(33); Numbers.add(55); Numbers.add(62); // apply removeIf() method // to remove numbers divisible by 2 Numbers.removeIf(n -> (n % 2 == 0)); System.out.println("All Numbers not divisible by 2 are:"); // print list for (int i : Numbers) { System.out.println(i); } }} |
All Numbers not divisible by 2 are: 33 55
Example 2: To demonstrate removeIf() method on Vector which contains set of Students Names and to remove all 4 char long name.
// Java Program Demonstrate removeIf()// method of Vector import java.util.*; public class GFG { public static void main(String[] args) { // create a Vector // containing a list of string values Vector<String> students = new Vector<String>(); // Add Strings to list // each string represents student name students.add("Rama"); students.add("Mohan"); students.add("Sohan"); students.add("Rabi"); students.add("Shabbir"); // apply removeIf() method // to remove names contains 4 chars students.removeIf(n -> (n.length() == 4)); System.out.println("Students name do not contain 4 char are"); // print list for (String str : students) { System.out.println(str); } }} |
Students name do not contain 4 char are Mohan Sohan Shabbir
Example 3: To demonstrate NullpointerException in removeIf() method on Vector.
// Java Program Demonstrate removeIf()// method of Vector import java.util.*; public class GFG { public static void main(String[] args) { // create a Vector // containing a list of string values Vector<String> students = new Vector<String>(); // Add Strings to list // each string represents student name students.add("Rama"); students.add("Mohan"); students.add("Sohan"); students.add("Rabi"); students.add("Shabbir"); try { // apply removeIf() method with null filter students.removeIf(null); } catch (Exception e) { System.out.println("Exception: " + e); } }} |
Exception: java.lang.NullPointerException
