EDUCBA

EDUCBA

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

Java newInstance()

By Priya PedamkarPriya Pedamkar

Home » Software Development » Software Development Tutorials » Java Tutorial » Java newInstance()

Java newInstance()

Introduction to Java newInstance()

Java newinstance() method of class comes into the picture whenever the class needs to create a new instance dynamically. This method will be called on top of the already existing method, which is the .class name used for loading any class dynamically. This newInstance() method will be called in addition to that class for creating objects dynamically. This newInstance () method of the class does not consider any parameters or arguments from the class, which means that it doesn’t possess any constructor; thus, it can be called the no-arg constructor for one class.

Syntax

Start Your Free Software Development Course

Web development, programming languages, Software testing & others

public Tsk newInstance() throws InitiationException, IllegalAccessException

The syntax flow consists of the following parameters, which represent:

  • Public: Access modifier for the class being defined and declared.
  • Tsk: Name of the class declared and is generic, which means it can think like an Object class and generics.
  • newInstance(): Name of the method called to create and load object dynamically with addition to the .class name of the class.
  • throws: keyword for catching and throwing Exceptions.
  • InitiationException: followed by throws keyword, it is used for catching Exceptions which get initiated initially.
  • IllegalAccessException: used for catching and accessing all the illegal or unused Exceptions.

How newInstance() method work in Java?

Any newInstance() of the class or the constructor both are called and is used for creating a new instance of the class. It is always preferred to use newInstance() method of the constructor rather than using the newInstance() method of the class because the newInstance() method of the constructor can make use of any number of arguments which is not the case with the newInstance() method of the class as the newInstance() method of the class doesn’t possess any argument which means no-arg constructor in the class. Also, sometimes it is compared and blended with the new Operator of any class.

The working flow of the newInstance() method is in this way where the new Operator is used for creating the objects, and then a decision is taken whether it is needed to create the object at run time or compile time or it is very much needed to create the object dynamically. If it is decided that the object is needed to be created at runtime, then the creation of a new Operator will be vague. Therefore, to create the object at runtime and to load the object dynamically, it is needed to create and make use of the newInstance() method.

As discussed, the newInstance() method of the class will first create an object of the class type and then be called using a .class name to create the new instance. Class.forName() method will return an object for the class, which will return the object of that class which is passed as an argument and if the class which passes the parameter does not exist, then it will throw an exception of ClassNotFoundException.

Instantiation Exception followed by throws will be called and used when the method internally calls for that class’s default constructor. IllegalAccessException will occur if there is no accessibility to the defined and specified class. Thus newInstance() method of the class is recommended because of the flexibility and versatility it provides for the creation of newInstance() of the object using dynamic loading. The typical behavior and the invocation of the constructors and object are different and enhancing as it doesn’t include any parameters to be passed to the methods and objects.

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 (9,005 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)

Examples of Java newInstance()

Here are the following examples mention below:

Example #1

This program is used to illustrate the Class.forName method with the newInstance method for creating the object and then print the object of that class for printing the value of the animal and creating it for the exceptions.

Code:

class Animal {  int p; }
class Birds {  int q; }
public class NewInstanceTst
{
public static void sounds(String s)  throws InstantiationException,
IllegalAccessException, ClassNotFoundException
{
Object obj_1 = Class.forName(s).newInstance();
System.out.println("Creation of newly instantiated class:"
+ obj_1.getClass().getName());
}
public static void main(String[] args) throws InstantiationException,
IllegalAccessException, ClassNotFoundException
{
sounds("Animal");
}
}

Output:

Java newInstance() output 1

Example #2

This program demonstrates the newInstance class of Java with passing parameters or constructors. Then it is used for dynamic allocation of the object but not used as it will throw illegal exceptions. A test class is written and executed to verify whether the instantiated class can handle the object’s dynamic loading.

Code:

import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
public class NwInstncWithconstructors {
public static void main(String[] args)
throws InstantiationException,
IllegalAccessException,
IllegalArgumentException,
InvocationTargetException
{
Constructor[] constructor_a  = Instnace_Constructor_Test.class.getConstructors();
Instnace_Constructor_Test animal = (Instnace_Constructor_Test)constructor_a[0].newInstance();
System.out.println(animal.content);
}
}
class Instnace_Constructor_Test {
String content;
public Instnace_Constructor_Test()
{
System.out.println("Create a new Instance:");
content = "new_instance_of_the_value";
}
}

Output:

Java newInstance() output 2

Example #3

This program also demonstrates the newInstance class of Java. Still, without passing parameters or constructors, it is used for the dynamic allocation of objects seamlessly and makes the overall class flexible for allocation. Still, if not used, it will throw illegal exceptions. A test class is written and executed to verify whether the instantiated class can handle the object’s dynamic loading. This program calls for a no-arg method which means newInstance class directly.

Code:

import java.lang.reflect.Constructor;
import java.lang.reflect.InvocationTargetException;
public class NewInstanceWithout_Constructors {
public static void main(String[] args)
throws InstantiationException,
IllegalAccessException,
IllegalArgumentException,
InvocationTargetException
{
Constructor[] constructor_without_arr = Without_constructor_Test.class.getConstructors();
Without_constructor_Test sm_ob
= (Without_constructor_Test)constructor_without_arr[0] .newInstance("one_field_value");
System.out.println(sm_ob.getthat_value());
}
}
class Without_constructor_Test {
private String that_value;
public Without_constructor_Test(String that_value)
{
this.that_value = that_value;
}
public String getthat_value()
{
return that_value;
}
public void setthat_value(String that_value)
{
this.that_value = that_value;
}
}

Output:

output 3

Note: It is always recommended to use a newInstance class instead of using a newInstance constructor because it can easily perform dynamic loading of the class and is flexible, unlike the newInstance constructor, which is not at all preferable if used with multiple parameters that too at the run time.

Conclusion

newInstance() method of java class is an added advantage as it is used to dynamically load the object without passing multiple parameters, and then it can be used with versatility within the class, and no external method is called at the run time with the help of .classForName method of the class the work gets solved relentlessly.

Recommended Articles

This is a guide to Java newInstance(). Here we discuss how the newInstance() method works in Java and examples for better understanding. You may also look at the following articles to learn more –

  1. Finally in Java
  2. Java max()
  3. copy() in Java
  4. Java min()

All in One Software Development Bundle (600+ Courses, 50+ projects)

600+ Online Courses

50+ projects

3000+ Hours

Verifiable Certificates

Lifetime Access

Learn More

3 Shares
Share
Tweet
Share
Primary Sidebar
Java Tutorial
  • 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
  • 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
  • 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
  • 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
  • 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 Course Learn More