EDUCBA

EDUCBA

MENUMENU
  • Free Tutorials
  • Free Courses
  • Certification Courses
  • 600+ Courses All in One Bundle
  • Login

Collection Interface in Java

By Priya PedamkarPriya Pedamkar

Home » Software Development » Software Development Tutorials » Java Tutorial » Collection Interface in Java

Collection Interface in Java

Introduction to Collection Interface in Java

The Collection Interface is the basic root interface of the Collection Framework and defines the basic methods that all members of the Collection Interface must use; the Collection Framework, which includes various ways of processing, manipulating and accessing data, is based on this Collection Interface.

Collection Interface in Java

Collection interface in java is available in java.util.Collection package and defines the basic methods that all members of the collection family need to implement.

Start Your Free Software Development Course

Web development, programming languages, Software testing & others

The following methods are defined in the collection interface and should be implemented by all collection frameworks.

Method Name Method Description
boolean add(Object object) This method adds the specified object to the collection calling this method. It returns true if the object was added to the collection otherwise returns false if the object is already a part of the collection or if the collection does not allow duplicates elements.
boolean addAll(Collection collection) This method adds all the elements of the specified collection to the collection calling this method. It returns true if the addition is successful, otherwise, it returns false.
boolean contains(Object object) This method returns true if the specified object is a part of the collection calling this method; otherwise, it returns false.
void clear( ) This method removes all elements from the collection calling this method.
boolean containsAll(Collection collection) This method returns true if the collection calling this method contains all specified collection elements; otherwise, it returns false.
boolean equals(Object object) This method returns true if the collection calling this method and the specified object are equal; otherwise, it returns false.
int hashCode( ) This method returns the hash code for the collection calling this method.
boolean isEmpty( ) This method returns true if the collection calling this method contains no elements; otherwise, it returns false.
Iterator iterator( ) This method returns an iterator for the collection calling this method.
boolean remove(Object object) This method removes the specified object from the collection calling this method. Returns true if the specified object was removed, otherwise returns false.
boolean removeAll(Collection collection) This method removes all elements available in a specified collection from the collection calling this method. Returns true if there is a change in collection calling this method; otherwise, it returns false.
boolean retainAll(Collection collection) This method removes all elements from the collection calling this method except those available in the specified collection. This method returns true if there is a change in collection calling this method; otherwise, it returns false.
int size( ) This method returns the number of elements available in the collection calling this method.
Object[ ] toArray( ) This method returns an array that contains all the elements stored in the collection calling this method. The array elements are, in fact, copies of the elements available in the calling collection.
Object[ ] toArray(Object array[ ]) This method returns an array containing only those collection elements of the calling collection whose type matches the type of elements in the specified array.

Examples of Collection Interface in Java

Given below are the examples of Collection Interface in Java:

Example #1

In this example, we will show methods of collection interface in java. We will see how to use add, addAll and size method.

Code:

package com.edubca.nonprimitivedemo;
// import collections
import java.util.ArrayList;
import java.util.List;
public class DataTypeDemo {
public static void main(String[] args) {
List arraylist1 = new ArrayList();
// Adding elements to arraylist
arraylist1.add("Yash");
arraylist1.add("Montu");
arraylist1.add("Ketan");
System.out.println(" ArrayList1 Elements are :");
System.out.println("\t" + arraylist1);
//printing size of arraylist1
System.out.println("Size of ArrayList1 is " +arraylist1.size() );
List arraylist2 = new ArrayList();
// Adding elements to arraylist
arraylist2.add("Chetan");
arraylist2.add("Chirag");
arraylist2.add("Ali");
System.out.println();
System.out.println(" ArrayList2 Elements are :");
System.out.println("\t" + arraylist2);
//printing size of arraylist2
System.out.println("Size of ArrayList1 is " +arraylist2.size() );
System.out.println();
// Adding elements of both lists to list1
arraylist1.addAll(arraylist2);
// Now Printing modified list
System.out.println(" ArrayList1 Elements after merging with ArrayList2 are : ");
System.out.println("\t" + arraylist1);
//printing size of arraylist1
System.out.println("Size of ArrayList1 is " +arraylist1.size() );
}
}

Output:

collection interface in java 1

Example #2

In this example, we will see some more methods of collection interface.

Popular Course in this category
Java Training (40 Courses, 29 Projects, 4 Quizzes)40 Online Courses | 29 Hands-on Projects | 285+ Hours | Verifiable Certificate of Completion | Lifetime Access | 4 Quizzes with Solutions
4.8 (9,016 ratings)
Course Price

View Course

Related Courses
JavaScript Training Program (39 Courses, 23 Projects, 4 Quizzes)jQuery Training (8 Courses, 5 Projects)Free Java Online CourseJavaFX Training (1 Courses)

Code:

package com.edubca.nonprimitivedemo;
// import collections
import java.util.ArrayList;
import java.util.List;
// importing iterator
import java.util.Iterator;
public class DataTypeDemo {
public static void main(String[] args) {
// creating array list of type string
ArrayList<String> arraylist1 = new ArrayList<String>();
arraylist1.add("Spark");
arraylist1.add("Hadoop");
arraylist1.add("Hive");
arraylist1.add("Kafka");
System.out.println("Elements of list1 are : " + arraylist1);
ArrayList<String> arraylist2 = new ArrayList<String>();
arraylist2.add("Spark");
arraylist2.add("Hadoop");
arraylist2.add("Hive");
arraylist2.add("Kafka");
boolean isequal=arraylist1.equals(arraylist2); // check if both lists are equal
System.out.println("Elements of list2 are : " + arraylist2);
System.out.println ("Are Both Lists equal? " + isequal);
arraylist1.addAll(arraylist2); // merging both lists
// iterating arraylist
Iterator it=arraylist1.iterator();
System.out.println("Iterating Elements of Arraylist:");
while(it.hasNext()){
System.out.println(it.next());
}
}
}

Output:

collection interface in java 2

Conclusion

The above article provides a clear understanding of the collection interface in java and the different methods available in the collection interface. Java code examples covered above shows how members of the collection family use methods of collection interface.

Recommended Articles

This is a guide to Collection Interface in Java. Here we discuss the basic concept, methods, and examples of collection interface in java with code and output. You may also have a look at the following articles to learn more –

  1. Queue in Java
  2. Java PrintWriter
  3. Iterator in Java
  4. Java RuntimeException

Java Training (40 Courses, 29 Projects, 4 Quizzes)

40 Online Courses

29 Hands-on Projects

285+ Hours

Verifiable Certificate of Completion

Lifetime Access

4 Quizzes with Solutions

Learn More

0 Shares
Share
Tweet
Share
Primary Sidebar
Java Tutorial
  • Advanced
    • Methods in Java
    • Serialization in Java
    • Inner Class in Java
    • Anonymous Inner Class in Java
    • Java Stack Methods
    • Java Static Nested Class
    • Synchronized Block in Java
    • Static Synchronization in Java
    • Abstract Class in Java
    • Access Modifiers in Java
    • Non Access Modifiers in Java
    • Bit Manipulation in Java
    • Encapsulation in Java
    • Singleton Class in Java
    • Wrapper Class in Java
    • Nested Class in Java
    • Java Matcher
    • Java Pattern Class
    • Java File Class
    • Final Class in Java
    • Stack Class in Java
    • Anonymous Class in Java
    • StringBuilder Class in Java
    • StringBuffer in Java
    • Java Directories
    • JSON in Java
    • Object Class in Java
    • What is Multithreading in java
    • Java Thread Priority
    • Daemon Thread in Java
    • Java Thread Pool
    • Java ThreadLocal
    • Association in Java
    • Queue in Java
    • Functional Programming in Java
    • ClassLoader in Java
    • Interface in Java
    • Functional Interface in Java
    • Java Queue Interface
    • Collection Interface in Java
    • Object Cloning in Java
    • Java.net URI
    • Java Assertion
    • Vector in Java
    • Applets in Java
    • Template in Java
    • Java Shutdown Hook
    • 2D Graphics in Java
    • Autoboxing and Unboxing in Java
    • Comparable in Java Example
    • Java Annotations
    • Java User Input
    • Serialization in Java
    • Dynamic Binding in Java
    • Java Parse String
    • Java Adapter Classes
    • Immutable Class in Java
    • String Initialization in Java
    • String Manipulation in Java
    • ThreadGroup in Java
    • Java Iterate Map
    • Java IO
    • Java?OutputStreamWriter
    • DataInputStream in Java
    • Java BufferedReader
    • Java BufferedWriter
    • Java BufferedInputStream
    • Java ByteArrayInputStream
    • Java ByteArrayOutputStream
    • Java RandomAcessFile
    • Java PrintStream
    • Java PrintWriter
    • Java URLEncoder
    • Java Scanner Class
    • Java Console
    • Java Runtime class
    • Java Base64
    • Java Base64 Encoding
    • Java Base64?Decode
    • Finalize in Java
    • Java Parallel Stream
    • Java Getter Setter
    • Set Interface in Java
    • How to Connect Database in Java
    • How to Create Webservice in Java
    • Composition in Java
    • BinarySearch() in Java
    • Exception Handling in Java
    • Java NullPointerException
    • Java NoSuchElementException
    • Java ConcurrentModificationException
    • Java ArithmeticException
    • Java IOException
    • Java RuntimeException
    • NumberFormatException in Java
    • Java ArrayIndexOutOfBoundsException
    • Java ClassNotFoundException
    • Java FileNotFoundException
    • Java InterruptedException
    • Finally in Java
    • Java Default Method
    • Java Locale
    • Tuples in Java
    • Java ServerSocket
    • Java Lambda Expressions
    • Java DatagramSocket
    • Java Animation
  • Basic
    • What is Java?
    • What is JNDI in Java
    • What is JNI in Java
    • What is Java Interface
    • What is Java SE
    • What is JavaBeans
    • Install JDK
    • Java Programming Language Features
    • Applications of Java
    • Career in Java
    • Versions of Java
    • Java Virtual Machine
    • Java GUI Framework
    • Java Packages
    • Java Package Example
    • Default Package in Java
    • Variables in Java
    • Instance Variable in Java
    • Object in Java
    • Java Commands
    • Iterator in Java
    • Java Booleans
    • Conversion in Java
    • Type Conversion in Java
    • String in Java
    • What is JDK
    • What is JVM
    • What is J2EE
    • RMI Architecture
    • Java Literals
    • Data Types in Java
    • Primitive Data Types in Java
    • Enumset in Java
    • Cheat Sheet Java
    • IntelliJ Cheat Sheet
  • Frameworks
    • Best Java Compilers
    • Frameworks In Java
    • Testing Frameworks for Java
    • Java Monitoring Tool
    • Best Java IDE
    • Java Compilers
    • Java Tools
    • Java Deployment Tools
    • Types of Memory in Java
    • Java References
    • Java Type Inference
    • Java Boolean to String
    • Java String to Float
    • java.net Package
    • Java Formatter
  • Operators
    • Arithmetic Operators in Java
    • Unary Operators in Java
    • Logical Operators in Java
    • Comparison Operators in Java
    • Assignment Operators in Java
    • Java String Operators
    • Conditional Operator in Java
    • Boolean operators in Java
  • Keywords
    • Java Keywords
    • this Keyword in Java
    • Static Keyword in Java
    • Native keyword in Java
    • Throw Keyword in Java
    • Throws Keyword in Java
    • What is public in Java?
    • Private in Java
    • Protected Keyword in Java
    • Final Keyword in Java
  • Control statements
    • Control Statement in Java
    • Else-If Statement in Java
    • Nested if Statements in Java
    • Continue Statement in Java
    • Break Statement in Java
    • Case Statement in Java
  • Loops
    • Loops in Java Programming
    • For Loop in Java
    • While Loop in Java
    • do-while loop in Java
    • For-Each loop in Java
    • Nested Loop in Java
  • Inheritance
    • Inheritance in Java
    • Single Inheritance in Java
    • Multilevel Inheritance in Java
    • Hierarchical Inheritance in Java
    • Hybrid Inheritance in Java
  • Constructor and destructor
    • Constructor and Destructor in Java
    • Constructor in Java
    • Destructor in Java
    • Copy Constructor In Java
    • Static Constructor in Java
    • Private Constructor in Java
  • Array
    • Arrays in Java Programming
    • 2D Arrays in Java
    • 3D Arrays in Java
    • Multidimensional Array in Java
    • Array Methods in Java
    • Print 2D Array in Java
    • Print Array in Java
    • String Array in Java
    • Associative Array in Java
    • Dynamic Array in Java
    • Java Array Iterator
    • Java array.push
    • Sort String Array in Java
  • Sorting
    • Sorting in Java
    • Sorting Algorithms in Java
    • Merge Sorting Algorithms in Java
    • Quick Sorting Algorithms in Java
    • Selection Sort In Java
    • Heap Sort In Java
    • Bubble Sort in Java
    • Merge Sort In Java
    • Quick Sort in Java
    • Insertion Sort in Java
    • Sort String in Java
    • Program for Merge Sort in Java
  • Functions
    • String Functions in java
    • Math Functions in Java
    • Hashing Function in Java
    • Regular Expressions in Java
    • Recursion in Java
    • Java Callback Function
    • Java Call by Value
    • Java Call by Reference
    • HashMap in Java
    • Java String Concatenation
    • Java String Equals
    • Compare two Strings in Java
    • Virtual Function in Java
    • Java newInstance()
    • split() Function in Java
    • trim() Function in Java
    • Replace() Function in Java
    • substring() Function in Java
    • Strictfp in Java
    • String Reverse Function in Java
    • Java String getBytes
    • Java Replace Char in String
    • Shuffle() in Java
    • addAll() in Java
    • FileWriter in Java
    • Java Stream Filter
    • Java FileInputStream
    • replaceAll() in Java
    • repaint in Java
    • copy() in Java
    • Java max()
    • Java min()
    • Java Timestamp
    • Java URLConnection
    • Java StringJoiner
    • Java KeyStore
    • Java InetAddress
    • Java getMethod()
    • swap() in Java
    • Deadlock in Java
    • Range in Java
    • Java Repository
    • Java Dictionary
    • Calculator in Java
    • Mutable String in Java
    • Mutable vs Immutable Java
    • Native Methods in Java
    • StringBuffer Class in Java
    • String Class in Java
    • Java URL Class
    • Java Vector Class
  • Polymorphism
    • What is Polymorphism
    • Polymorphism in Java
    • Runtime Polymorphism in Java
    • Overloading and Overriding in Java
    • Overloading in Java
    • Method Overloading in Java
    • Function Overloading in Java
    • Overriding in Java
    • Method Overriding in Java
    • Final Keyword in Java
    • Super Keyword in Java
    • instanceOf in Java
    • Java Authenticator
    • Java Alias
  • Collections
    • What is TreeMap in Java?
    • Sorting in Collection
    • Java Collections Class
    • Hashtable in Java
    • Java EnumMap
    • Java LinkedHashMap
    • Reverse Linked List in Java
    • LinkedList in Java
  • Date Time
    • java.util.Date
    • Java Clock
    • Java Instant
    • Java LocalTime
    • Java ZoneId
    • Java ZoneOffset
    • Java varargs
    • Java LocalDate
    • Java OffsetDateTime
    • Java LocalDateTime
    • Java Duration
    • Java DayOfWeek
    • Java Period
    • Timer in Java
    • Java TimeZone
    • Java Date Picker
  • MISc
    • What is Synchronization in Java
    • What is Concurrency in Java
    • What is Design Pattern in Java
    • What is Generics in Java
    • What is API in Java
    • What is a Binary Tree in Java
    • What is Java Garbage Collector
    • What is Java Inheritance
    • Thread Life cycle in Java
    • Object Oriented Programming in Java
    • Java App Development
    • Java Naming Conventions
    • Java hashCode()
    • Java Transient
    • JSTL In Java
    • Comparable in Java 
    • Aggregation in Java
    • EJB in Java
    • @deprecated in Java
    • Java @Inherited
    • @SuppressWarnings in Java
    • Java @Override
  • Programs
    • Patterns in Java
    • Star Patterns in Java
    • Number Patterns in Java
    • Swapping in Java
    • Factorial in Java
    • Fibonacci Series in Java
    • Reverse Number in Java
    • Palindrome in Java
    • Armstrong Number in Java
    • Squares in Java
    • Square Root in Java
    • Special Number in Java
    • Anagram Program in Java
    • Strong Number in Java
    • Random Number Generator in Java
    • Matrix Multiplication in Java
    • Socket Programming in Java
    • Prime Numbers in Java
    • String Comparison in Java
    • Leap Year Program in Java
    • Reverse String in Java
    • Design Patterns in Java
    • Happy Numbers in Java
  • Interview Questions
    • Java Interview Questions
    • Java Inheritance Interview Questions
    • Java EE Interview Questions
    • Java Developer Interview Questions
    • Java Collection Interview Questions
    • Java Interview Question on Multithreading
    • Java String interview question
    • Java Testing Interview Questions
    • Java Multi-threading Interview Questions
    • Multithreading Interview Questions in Java
    • Oops Java Interview Questions
    • Java Spring Interview Questions
    • Data Structure Java Interview Questions
    • Java Web Services Interview Questions

Related Courses

Java Course

JavaScript Certification Course

jQuery Training Course

Java Training Courses

Free Java Training Courses

JavaFX Training

Java Training Course

Footer
About Us
  • Blog
  • Who is EDUCBA?
  • Sign Up
  • Corporate Training
  • Certificate from Top Institutions
  • Contact Us
  • Verifiable Certificate
  • Reviews
  • Terms and Conditions
  • Privacy Policy
  •  
Apps
  • iPhone & iPad
  • Android
Resources
  • Free Courses
  • Java Tutorials
  • Python Tutorials
  • All Tutorials
Certification Courses
  • All Courses
  • Software Development Course - All in One Bundle
  • Become a Python Developer
  • Java Course
  • Become a Selenium Automation Tester
  • Become an IoT Developer
  • ASP.NET Course
  • VB.NET Course
  • PHP Course

© 2020 - EDUCBA. ALL RIGHTS RESERVED. THE CERTIFICATION NAMES ARE THE TRADEMARKS OF THEIR RESPECTIVE OWNERS.

EDUCBA Login

Forgot Password?

EDUCBA
Free Software Development Course

Web development, programming languages, Software testing & others

*Please provide your correct email id. Login details for this Free course will be emailed to you
Book Your One Instructor : One Learner Free Class

Let’s Get Started

This website or its third-party tools use cookies, which are necessary to its functioning and required to achieve the purposes illustrated in the cookie policy. By closing this banner, scrolling this page, clicking a link or continuing to browse otherwise, you agree to our Privacy Policy

EDUCBA

*Please provide your correct email id. Login details for this Free course will be emailed to you
EDUCBA
Free Software Development Course

Web development, programming languages, Software testing & others

*Please provide your correct email id. Login details for this Free course will be emailed to you

Special Offer - Java Training (40 Courses, 29 Projects, 4 Quizzes) Learn More