Get, Add, Remove, Retain, Sort & iterate methods of arraylist collection (java/ example)

1. ArrayList class is resizable array implementation of the List interface.
2. ArrayList maintains the insertion order of element or string objects.
3. ArrayList allows the duplicate elements & we can randomly access elements by index.
4. ArrayList is not thread safe.
   • If multiple threads access an ArrayList instance concurrently, then arraylist must be synchronized externally.
5. Given an arraylist collection, we would demonstrate the following operations on arraylist.
   • Remove
   • Add
   • Retain
   • Sort
   • Iterate
   • Get
   • Contains And
   • Clear

1. Class Hierarchy of ArrayList Collection:

2. Add,sort,iterate,get,contains,clear methods of arraylist (java /example)

package org.learn.collection.list.arrayList;

import java.util.ArrayList;
import java.util.Collections;
import java.util.ListIterator;

public class DemoArrayList {

	public static void main(String[] args) {
		ArrayList<String> arrayList = new ArrayList<>();
		arrayList.add("archery");
		arrayList.add("badminton");
		arrayList.add("canoe");
		arrayList.add("boxing");
		arrayList.add("diving");
		arrayList.add("beach volleyball");

		System.out.println("1. Demo of remove methods of ArrayList: ");
		demoRemoveMethod(arrayList);

		System.out.println("\n2. Demo of add methods of ArrayList: ");
		demoAddMethod(arrayList);

		System.out.println("\n3. Demo of retain method of ArrayList: ");
		demoRetainAll(arrayList);

		System.out.println("\n4. Sort elements of arrayList collection: ");
		demoSortMethod(arrayList);

		System.out.println("\n5. Iterate through arrayList collection: ");
		demoIterateMethod(arrayList);

		System.out.println("\n6. Demo of get method of arraylist collection: ");
		System.out.println("Element at index 0: " + arrayList.get(0));
		System.out.println("Element at index 2: " + arrayList.get(2));

		System.out.println("\n7. Demo of contains method of arraylist collection: ");
		System.out.println("Check arraylist contains diving: " + arrayList.contains("diving"));
		System.out.println("Check arraylist contains soccer: " + arrayList.contains("archery"));

		System.out.println("\n8.Demo of clear method of arraylist collection: ");
		arrayList.clear();
		System.out.println("Clear arrayList: " + arrayList);
	}

	private static void demoRemoveMethod(ArrayList<String> arrayList) {
		// [archery, badminton, canoe, boxing, diving, beach volleyball]
		System.out.println("Orignal ArrayList:" + arrayList);

		// Remove element by index
		arrayList.remove(0);
		// [badminton, canoe, boxing, diving, beach volleyball]
		System.out.println("Removed element at 0 index: " + arrayList);

		// Remove element after comparing and remove it
		arrayList.remove("boxing");
		// [badminton, canoe, diving, beach volleyball]
		System.out.println("Removed boxing from arrayList: " + arrayList);

		ArrayList<String> removeElementsList = new ArrayList<>();
		removeElementsList.add("canoe");
		removeElementsList.add("diving");
		removeElementsList.add("beach volleyball");

		// Remove element by supplying another collection
		arrayList.removeAll(removeElementsList);

		// [badminton]
		System.out.println("Removed collection containing canoe and diving: " + arrayList);
	}

	private static void demoAddMethod(ArrayList<String> arrayList) {
		//[badminton]
		System.out.println("Orignal ArrayList:" + arrayList);
		arrayList.add(0, "archery");
		arrayList.add(2, "canoe");
		// [archery, badminton, canoe]
		System.out.println("Added element at 0,2 index: " + arrayList);

		arrayList.add("diving");
		// [archery, badminton, canoe, diving]
		System.out.println("Added element in list: " + arrayList);

		ArrayList<String> addElementsList = new ArrayList<>();
		addElementsList.add("squash");
		addElementsList.add("bowling");

		// It will add elements to last of list
		arrayList.addAll(addElementsList);
		// [archery, badminton, canoe, diving, squash, bowling]
		System.out.println("Added another list : " + arrayList);

		ArrayList<String> anotherList = new ArrayList<>();
		anotherList.add("golf");
		anotherList.add("judo");

		// It will add elements to last of list
		arrayList.addAll(1, anotherList);
		//[archery, golf, judo, badminton, canoe, diving, squash, bowling]
		System.out.println("Added another list at index 1 : " + arrayList);
	}

	private static void demoRetainAll(ArrayList<String> arrayList) {
		//[archery, golf, judo, badminton, canoe, diving, squash, bowling]
		System.out.println("Orignal ArrayList:" + arrayList);
		ArrayList<String> retainSportsList = new ArrayList<>();
		retainSportsList.add("soccer");
		retainSportsList.add("judo");
		retainSportsList.add("archery");
		retainSportsList.add("badminton");
		arrayList.retainAll(retainSportsList);
		// [archery, judo, badminton]
		System.out.println("Retaining elements soccer, judo and archery list: " + arrayList);
	}

	private static void demoSortMethod(ArrayList<String> arrayList) {
		// [archery, judo, badminton]
		System.out.println("Orignal ArrayList:" + arrayList);
		Collections.sort(arrayList);
		//[archery, badminton, judo]
		System.out.println("Sort ascending order: " + arrayList);

		Collections.sort(arrayList, Collections.reverseOrder());
		//[judo, badminton, archery]
		System.out.println("Sort desending order: " + arrayList);
	}

	private static void demoIterateMethod(ArrayList<String> arrayList) {

		System.out.println("Iterating using forEachRemaining:");
		// Output of for loop:
		// judo badminton archery 
		arrayList.forEach(element -> System.out.printf("%s ", element));

		System.out.println("\nIterating arrayList using foreach loop:");
		// Output of for loop:
		// judo badminton archery 
		for (String element : arrayList) {
			System.out.printf("%s ", element);
		}

		System.out.println("\nIterating arrayList using iterator:");
		ListIterator<String> listIterator = arrayList.listIterator();
		// Output of while loop:
		// judo badminton archery 
		while (listIterator.hasNext()) {
			System.out.printf("%s ", listIterator.next());
		}
		System.out.println("");
	}

}

3. Add,sort,iterate,get,contains,clear methods of arraylist (java /example)

1. Demo of remove methods of ArrayList: 
Orignal ArrayList:[archery, badminton, canoe, boxing, diving, beach volleyball]
Removed element at 0 index: [badminton, canoe, boxing, diving, beach volleyball]
Removed boxing from arrayList: [badminton, canoe, diving, beach volleyball]
Removed collection containing canoe and diving: [badminton]

2. Demo of add methods of ArrayList: 
Orignal ArrayList:[badminton]
Added element at 0,2 index: [archery, badminton, canoe]
Added element in list: [archery, badminton, canoe, diving]
Added another list : [archery, badminton, canoe, diving, squash, bowling]
Added another list at index 1 : [archery, golf, judo, badminton, canoe, diving, squash, bowling]

3. Demo of retain method of ArrayList: 
Orignal ArrayList:[archery, golf, judo, badminton, canoe, diving, squash, bowling]
Retaining elements soccer, judo and archery list: [archery, judo, badminton]

4. Sort elements of arrayList of ArrayList: 
Orignal ArrayList:[archery, judo, badminton]
Sort ascending order: [archery, badminton, judo]
Sort desending order: [judo, badminton, archery]

5. Iterate through arrayList collection: 
Iterating using forEachRemaining:
judo badminton archery 
Iterating arrayList using foreach loop:
judo badminton archery 
Iterating arrayList using iterator:
judo badminton archery 

6. Demo of get method of arraylist collection: 
Element at index 0: judo
Element at index 2: archery

7. Demo of contains method of arraylist collection: 
Check arraylist contains diving: false
Check arraylist contains soccer: true

8.Demo of clear method of arraylist collection: 
Clear arrayList: []