How to clear Arraylist in java
To clear ArrayList in java we have 2 ways
1.
void clear() – Clears all the elements that are present in the ArrayList
2. boolean removeAll(Collection<?> c) – Removes those elements that are passed in as param and are available in the ArrayList.
Now lets see some examples of these methods
1. Clear Arraylist in java using clear()
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 | package com.kscodes.sampleproject; import java.util.ArrayList; import java.util.List; public class ArrayListClear { public static void main(String[] args) { List<String> arrayList1 = new ArrayList<>(); arrayList1.add("Java"); arrayList1.add("JSP"); arrayList1.add("JavaScript"); System.out.println("ArrayList contains following elements :: " + arrayList1); arrayList1.clear(); System.out.println("After calling clear() ArrayList contains following elements :: " + arrayList1); } } |
Output
1 2 | ArrayList contains following elements :: [Java, JSP, JavaScript] After calling clear() ArrayList contains following elements :: [] |
2.Clear Arraylist in java using removeAll()
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 | package com.kscodes.sampleproject; import java.util.ArrayList; import java.util.List; public class ArrayListClear { public static void main(String[] args) { List<String> arrayList1 = new ArrayList<>(); arrayList1.add("Java"); arrayList1.add("JSP"); arrayList1.add("JavaScript"); System.out.println("ArrayList contains following elements :: " + arrayList1); arrayList1.removeAll(arrayList1); System.out.println("After calling removeAll() ArrayList contains following elements :: " + arrayList1); } } |
Output
1 2 | ArrayList contains following elements :: [Java, JSP, JavaScript] After calling removeAll() ArrayList contains following elements :: [] |