How To Bring Together 2 Arraylist Inwards Coffee - Example

You tin purpose the addAll() method from java.util.Collection interface to bring together 2 ArrayLists inwards Java. Since ArrayList implements List interface which truly extends the Collection interface, this method is available to all List implementation including ArrayList e.g. Vector, LinkedList. The Collection.addAll(Collection src) method takes a collection together with adds all elements from it to the collection which calls this method e.g. target.addAll(source). After this call, the target volition receive got all elements from both beginning together with target ArrayList, which is similar joining 2 ArrayList inwards Java. The minute ArrayList volition stay every bit it is but the starting fourth dimension ArrayList on which y'all receive got added elements volition receive got to a greater extent than elements. Its size volition live on equal to the total of the size of starting fourth dimension together with minute ArrayList.

You should remember, that amongst Generics inwards house y'all cannot bring together 2 dissimilar types of ArrayList e.g. y'all cannot bring together an Integer ArrayList to String ArrayList or vice-versa. If y'all desire to do a heterogeneous ArrayList, thence y'all should do 2 ArrayList of objects together with bring together them together every bit shown below:

List<Object> list1 = new ArrayList<Object>(); List<Object> list2 = new ArrayList<Object>();  list1.addAll(list2); // right away list1 has chemical factor of both listing 1 together with listing 2 

This ArrayList tin incorporate whatever type of object e.g. Integer, String, Float, together with Double. You tin besides read Big Java: Early Objects fifth Edition past times Cay S. Horstmann, a comprehensive guide of Java amongst lots of exercise questions, quizzes, together with diagrams.

Java Program to bring together ArrayList - ArrayList.addAll() Example

Here is a uncomplicated Java programme to demonstrate how to purpose addAll() method of Collection interface to bring together elements of 2 array listing inwards Java. In this program, nosotros receive got 2 ArrayList objects, starting fourth dimension contains some U.K. based banks e.g. Barclays, Standard Chartered, together with HSBC, spell the minute listing contains some U.S.A. based banks e.g. Citigroup, Chase, Wells Fargo, together with Bank of America. We finally do an ArrayList of global banks past times joining U.S.A. together with U.K. based banking concern together using addAll() method.

The inwards a higher house event is a truly skillful scenario of when y'all should bring together ArrayList or whatever other type of List implementation e.g. to do a large listing from 2 smaller lists. If y'all desire to larn to a greater extent than most ArrayList shape together with its usages inwards Java application, see Big Java: Early Objects past times Cay S. Horstmann , i of the most comprehensive guides of Java programming language.

Joining ArrayList inwards Java using Collection.addAll() 

import java.util.ArrayList; import java.util.List;  /*  * Java Program to bring together 2 ArrayLists into i   */  public class ArrayListJoiner {    public static void main(String[] args) {      // starting fourth dimension ArrayList     List<String> UKBasedBanks = new ArrayList<>();     UKBasedBanks.add("Standard Charated");     UKBasedBanks.add("HSBC");     UKBasedBanks.add("Barclays");      // minute ArrayList     List<String> USABanks = new ArrayList<>();     USABanks.add("Citibank");     USABanks.add("Chase");     USABanks.add("Bank of America");     USABanks.add("Wells Fargo");      System.out.println("first arraylist earlier joining : ");     System.out.println(UKBasedBanks);     System.out.println("second arraylist earlier joining : ");     System.out.println(USABanks);      // Joining 2 ArrayList     // adding all elements of USABanks listing to     // UKBasedBanks     UKBasedBanks.addAll(USABanks);      System.out.println("first arraylist later on joining : ");     System.out.println(UKBasedBanks);     System.out.println("second arraylist later on joining : ");     System.out.println(USABanks);    }  }  Output first ArrayList earlier joining :  [Standard Charted, HSBC, Barclays] minute ArrayList earlier joining :  [Citibank, Chase, Bank of America, Wells Fargo] first ArrayList later on joining :  [Standard Charted, HSBC, Barclays, Citibank, Chase, Bank of America, Wells Fargo] minute ArrayList later on joining :  [Citibank, Chase, Bank of America, Wells Fargo]

That's all about how to bring together 2 array lists inwards Java. You tin purpose this technique to bring together non entirely lists but besides whatever collection because addAll() method is defined on the Collection interface it's available to list, set, together with queue. Just hollo back that the beginning ArrayList volition stay intact but target ArrayList volition live on modified to include elements from beginning ArrayList.

Related Java ArrayList Tutorials for Programmers

• How to traverse an ArrayList inwards Java? (example)
• How to kind an ArrayList inwards Java? (example)
• How to contrary an ArrayList inwards Java? (example)
• How to synchronize an ArrayList inwards Java? (example)
• How to take objects from ArrayList inwards Java? (solution)
• How to take duplicates from ArrayList inwards Java? (solution)
• How to brand an ArrayList read-only inwards Java? (solution)
• How to acquire the starting fourth dimension together with in conclusion chemical factor of ArrayList inwards Java? (example)
• How to do together with initialize an ArrayList inwards the same line? (answer)

Further Learning
Java In-Depth: Become a Complete Java Engineer
Java Fundamentals: Collections
Data Structures together with Algorithms: Deep Dive Using Java