java lists code example

Example 1: Lists inside lists in java

public class GuiTest {

	
	public static void main(String[] args) {
		List<List<Integer>> MainList = new ArrayList<List<Integer>>();
		Random NewRandomNumber = new Random();
		
		for (int i = 0; i < 10; i++) {
			List<Integer> SecondList = new ArrayList<Integer>();
			MainList.add(SecondList);
			for (int i2 = 0; i2 < 10; i2++) {
				SecondList.add(NewRandomNumber.nextInt(6));
			}
		}

Example 2: list in java

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.ListIterator;
public class Main {
   public static void main(String[] args) {
      List<String> list = new ArrayList<String>();
      list.add("a");
      list.add("b");
      list.add("c");
      list.add("d");
      list.add("e");
      list.add("f");
      
      //On met la liste dans le désordre
      Collections.shuffle(list);
      System.out.println(list);
      
      //On la remet dans l'ordre
      Collections.sort(list);
      System.out.println(list);
      
      Collections.rotate(list, -1);
      System.out.println(list);
      
      //On récupère une sous-liste
      List<String> sub = list.subList(2, 5);
      System.out.println(sub);
      Collections.reverse(sub);
      System.out.println(sub);
      
      //On récupère un ListIterator
      ListIterator<String> it = list.listIterator();
      while(it.hasNext()){
         String str = it.next();
         if(str.equals("d"))
            it.set("z");
      }
      while(it.hasPrevious())
         System.out.print(it.previous());
      
   }
}

Example 3: java append to list

package com.journaldev.examples;

import java.util.ArrayList;
import java.util.List;

public class ListAddExamples {

	public static void main(String[] args) {

		List<String> vowels = new ArrayList<>();

		vowels.add("A"); // [A]
		vowels.add("E"); // [A, E]
		vowels.add("U"); // [A, E, U]

		System.out.println(vowels); // [A, E, U]

		vowels.add(2, "I"); // [A, E, I, U]
		vowels.add(3, "O"); // [A, E, I, O, U]

		System.out.println(vowels); // [A, E, I, O, U]
	}
}

Example 4: java list

import java.util.*;
var list = new ArrayList<String>();
list.add("Hello World!");

Example 5: list in java

LIST: Can store duplicate values,
      Keeps the insertion order. 
      It allows multiple null values, 
      Also we can read a certain value by index.
- ArrayList not syncronized, array based class 
- LinkedList not synchronized, doubly linked
- Vector is synchronized, thread safe

Example 6: java list of objects example

List<Object> listAnything = new ArrayList<Object>();
List<String> listWords = new ArrayList<String>();
List<Integer> listNumbers = new ArrayList<Integer>();
List<String> linkedWords = new LinkedList<String>();