In this core java training session, you will learn OOP with Java Contd. Topics covered in this session are:
• Review of last class concepts
• Types of Inheritance and a look at Aggregation
• Polymorphism
• Method overloading
• Method overriding
For more information about this course visit on this link: https://www.mindsmapped.com/courses/software-development/learn-java-fundamentals-hands-on-training-on-core-java-concepts/
In this core java training session, you will learn Collections – Lists, Sets. Topics covered in this session are:
• List – ArrayList, LinkedList
• Set – HashSet, LinkedHashSet, TreeSet
For more information about this course visit on this link: https://www.mindsmapped.com/courses/software-development/learn-java-fundamentals-hands-on-training-on-core-java-concepts/
Every value in Java has a data type. Java supports two kinds of data types: primitive data types and reference data types. Primitive data types represent atomic, indivisible values. Java has eight Numeric data types: byte, short, int,
An operator is a symbol that is used to perform some type of computation on its operands. Java contains a rich set of
operators. Operators are categorized as unary, binary, or ternary based on the number of operands they take. They are categorized as arithmetic, relational, logical, etc. based on the operation they perform on their operands.
long, float, double, char, and boolean. Literals of primitive data types are constants. Reference data types represent
references of objects in memory. Java is a statically typed programming language. That is, it checks the data types of all values at compile time.
oops concept in java | object oriented programming in javaCPD INDIA
object oriented programming is a key concept for the development of application in windows as well as web based application environment. oops concept maps real world through its concept of classes, objects, inheritance, polymorphism which help in making a robust application.
In this core java training session, you will learn Collections – Lists, Sets. Topics covered in this session are:
• List – ArrayList, LinkedList
• Set – HashSet, LinkedHashSet, TreeSet
For more information about this course visit on this link: https://www.mindsmapped.com/courses/software-development/learn-java-fundamentals-hands-on-training-on-core-java-concepts/
Every value in Java has a data type. Java supports two kinds of data types: primitive data types and reference data types. Primitive data types represent atomic, indivisible values. Java has eight Numeric data types: byte, short, int,
An operator is a symbol that is used to perform some type of computation on its operands. Java contains a rich set of
operators. Operators are categorized as unary, binary, or ternary based on the number of operands they take. They are categorized as arithmetic, relational, logical, etc. based on the operation they perform on their operands.
long, float, double, char, and boolean. Literals of primitive data types are constants. Reference data types represent
references of objects in memory. Java is a statically typed programming language. That is, it checks the data types of all values at compile time.
oops concept in java | object oriented programming in javaCPD INDIA
object oriented programming is a key concept for the development of application in windows as well as web based application environment. oops concept maps real world through its concept of classes, objects, inheritance, polymorphism which help in making a robust application.
This is the presentation file about inheritance in java. You can learn details about inheritance and method overriding in inheritance in java. I think it's can help your. Thank you.
In this core java training session, you will learn Elements of Java programming. Topics covered in this session are:
• Quick review of some important concepts from last class
• History of Java
• JDK and JRE
• Byte Code and JVM (Java Virtual Machine)
• Platform Independence
• Principles of Object Oriented Programming
• Writing your first Java Application
• Elements of Java programming language
• Built in Data Types
• Conditional Statements
• Loops
For more information about this course visit on this link: https://www.mindsmapped.com/courses/software-development/learn-java-fundamentals-hands-on-training-on-core-java-concepts/
Java Collections | Collections Framework in Java | Java Tutorial For Beginner...Edureka!
**** Java Certification Training: https://www.edureka.co/java-j2ee-soa-training ****
This Edureka tutorial on “Java Collections” will talk about the complete hierarchy of Collections Frameworks in Java. It will walk you through the various fundamentals of collections like Lists, Queue, Sets, Interfaces etc. Through this tutorial you will learn the following topics:
Java Collection Framework
Collection Framework Hierarchy
Interfaces
List
Queue
Set
Check out our Java Tutorial blog series: https://goo.gl/osrGrS
Check out our complete Youtube playlist here: https://goo.gl/gMFLx3
Java Classes | Java Tutorial for Beginners | Java Classes and Objects | Java ...Edureka!
This Edureka 'Java Classes' tutorial will take you through in-depth details of Java classes and different key-components in Java. It is ideal for both beginners and professionals who want to learn or brush up the basics of Java. Below are the topics covered in this tutorial:
1. Classes in Java
2. Constructors
3. Structure of a Class
4. Overview of Objects
5. Working with Objects
6. Multiple classes
7. OOPS concepts: Inheritance, Encapsulation, Abstraction, Interface
Selection Statements
Using if and if...else
Nested if Statements
Using switch Statements
Conditional Operator
Repetition Statements
Looping: while, do, and for
Nested loops
Using break and continue
OOPS Concepts, Java Evolution, Class Object basic, Class Object Constructor overloading, Inheritance, Array and String, Final Abstract class and interfaces, Exceptions, Streams, GUI Applications, Applet Programming, Network Programming and Java Sockets, Multi Threading
Slides for a lightning talk on Java 8 lambda expressions I gave at the Near Infinity (www.nearinfinity.com) 2013 spring conference.
The associated sample code is on GitHub at https://github.com/sleberknight/java8-lambda-samples
From this slide you can know about
- Signature
- Polymorphism
-Method
-Types of Method
- Method Overloading
- Sample programme
- Reference Books & websites name
I hope, it is beneficial for beginner Java learner. It's just a simple overview of the topic Method Overloading in Java.
In this session, you will learn:
1. Deep dive into coding OOP with Java… with practical examples.
2. How to create a class
3. How to create objects
4. How to create instance variables
5. How to create class variables
6. Constructors
In this session you will learn:
Deep dive into coding OOP with Java… with practical examples.
How to create a class
How to create objects
How to create instance variables
How to create class variables
Constructors
For more information: https://www.mindsmapped.com/courses/software-development/become-a-java-developer-hands-on-training/
This is the presentation file about inheritance in java. You can learn details about inheritance and method overriding in inheritance in java. I think it's can help your. Thank you.
In this core java training session, you will learn Elements of Java programming. Topics covered in this session are:
• Quick review of some important concepts from last class
• History of Java
• JDK and JRE
• Byte Code and JVM (Java Virtual Machine)
• Platform Independence
• Principles of Object Oriented Programming
• Writing your first Java Application
• Elements of Java programming language
• Built in Data Types
• Conditional Statements
• Loops
For more information about this course visit on this link: https://www.mindsmapped.com/courses/software-development/learn-java-fundamentals-hands-on-training-on-core-java-concepts/
Java Collections | Collections Framework in Java | Java Tutorial For Beginner...Edureka!
**** Java Certification Training: https://www.edureka.co/java-j2ee-soa-training ****
This Edureka tutorial on “Java Collections” will talk about the complete hierarchy of Collections Frameworks in Java. It will walk you through the various fundamentals of collections like Lists, Queue, Sets, Interfaces etc. Through this tutorial you will learn the following topics:
Java Collection Framework
Collection Framework Hierarchy
Interfaces
List
Queue
Set
Check out our Java Tutorial blog series: https://goo.gl/osrGrS
Check out our complete Youtube playlist here: https://goo.gl/gMFLx3
Java Classes | Java Tutorial for Beginners | Java Classes and Objects | Java ...Edureka!
This Edureka 'Java Classes' tutorial will take you through in-depth details of Java classes and different key-components in Java. It is ideal for both beginners and professionals who want to learn or brush up the basics of Java. Below are the topics covered in this tutorial:
1. Classes in Java
2. Constructors
3. Structure of a Class
4. Overview of Objects
5. Working with Objects
6. Multiple classes
7. OOPS concepts: Inheritance, Encapsulation, Abstraction, Interface
Selection Statements
Using if and if...else
Nested if Statements
Using switch Statements
Conditional Operator
Repetition Statements
Looping: while, do, and for
Nested loops
Using break and continue
OOPS Concepts, Java Evolution, Class Object basic, Class Object Constructor overloading, Inheritance, Array and String, Final Abstract class and interfaces, Exceptions, Streams, GUI Applications, Applet Programming, Network Programming and Java Sockets, Multi Threading
Slides for a lightning talk on Java 8 lambda expressions I gave at the Near Infinity (www.nearinfinity.com) 2013 spring conference.
The associated sample code is on GitHub at https://github.com/sleberknight/java8-lambda-samples
From this slide you can know about
- Signature
- Polymorphism
-Method
-Types of Method
- Method Overloading
- Sample programme
- Reference Books & websites name
I hope, it is beneficial for beginner Java learner. It's just a simple overview of the topic Method Overloading in Java.
In this session, you will learn:
1. Deep dive into coding OOP with Java… with practical examples.
2. How to create a class
3. How to create objects
4. How to create instance variables
5. How to create class variables
6. Constructors
In this session you will learn:
Deep dive into coding OOP with Java… with practical examples.
How to create a class
How to create objects
How to create instance variables
How to create class variables
Constructors
For more information: https://www.mindsmapped.com/courses/software-development/become-a-java-developer-hands-on-training/
Object Oriented Concepts required to know about the Android Application Programming are discussed over here. Get the most of the details about each and every concept of OO paradigm so you can use them very well in Android Application Programming.
In this Java Spring Training session, you will learn Spring MVC. Topics covered in this session are:
For more information, visit this link:
• Spring framework
• Inversion of Control
• Dependency Injection – Two types
• Defining beans using XML
• Inheriting beans
• Auto-wiring
• Annotations based configuration
• Java based configuration
• Spring AOP
https://www.mindsmapped.com/courses/software-development/spring-fundamentals-learn-spring-framework-and-spring-boot/
In this Java Spring Training session, you will learn Spring AOP – Aspect Oriented Programming Topics covered in this session are:
For more information, visit this link:
• Auto-wiring
• Annotations based configuration
• Java based configuration
https://www.mindsmapped.com/courses/software-development/spring-fundamentals-learn-spring-framework-and-spring-boot/
Spring - Part 2 - Autowiring, Annotations, Java based Configuration - slidesHitesh-Java
In this Java Spring Training session, you will learn Spring AOP – Aspect Oriented Programming. Topics covered in this session are:
For more information, visit this link:
• Spring framework
• Inversion of Control
• Dependency Injection – Two types
• Defining beans using XML
• Inheriting beans
• Auto-wiring
• Annotations based configuration
• Java based configuration
https://www.mindsmapped.com/courses/software-development/spring-fundamentals-learn-spring-framework-and-spring-boot/
In this Java Spring Training session, you will learn Spring – Inversion of Control, Dependency Injection and Bean definitions. Topics covered in this session are:
For more information, visit this link:
Spring Framework
• Core Container
• Data Access/Integration
• Web Layer
• Spring Setup
• Key features
• Spring Bean
• Dependency Injection
• Relation between DI and IoC
• Spring IoC Containers
• Spring DI
https://www.mindsmapped.com/courses/software-development/spring-fundamentals-learn-spring-framework-and-spring-boot/
In this Java JSP Training session, you will learn JSP. Topics covered in this session are:
• JSP vs Servlet
• LifeCycle of Servlet
• JSP Elements
• JSP Page directive
• Directives vs Action tags
For more information, visit this link:
https://www.mindsmapped.com/courses/software-development/jsp-and-servlets-designing-web-applications-with-java/
In this Java JSP Training session, you will learn JSP. Topics covered in this session are:
• JSP (Java Server Pages Technology)
• JSP vs Servlet
• MVC Architecture
• Scriplet
For more information, visit this link:
https://www.mindsmapped.com/courses/software-development/jsp-and-servlets-designing-web-applications-with-java/
In this Java Hibernate Training session, you will learn Introducing Struts Framework. Topics covered in this session are:
• Introduction to Struts Framework
• Features
• Evolution
• Struts Demo
• Declarative validation
• Architecture
• Validators
• Interceptors
For more information, visit this link:
https://www.mindsmapped.com/courses/software-development/learn-hibernate-fundamentals-from-scratch/
In this Java Hibernate Training session, you will learn Integrating Struts with Hibernate. Topics covered in this session are:
• Struts 2
• Struts Action Class
• Validation
• Control Tags
• Data Tags
For more information, visit this link:
https://www.mindsmapped.com/courses/software-development/learn-hibernate-fundamentals-from-scratch/
In this Java Hibernate Training session, you will learn Hibernate part -2. Topics covered in this session are:
• Generator Class in Hibernate
• SQL Dialects
• Collection Mapping
• One-to-one Mapping
• Cascade Types
• Many to one / One to many
• Hibernate Lazy Loading
• Transaction Management
• HQL – Hibernate Query Language
• HCQL – Hibernate Criteria Query Language
• Hibernate Caching
For more information, visit this link:
https://www.mindsmapped.com/courses/software-development/learn-hibernate-fundamentals-from-scratch/
In this Java Hibernate Training session, you will learn Hibernate. Topics covered in this session are:
• Hibernate
• Advantage of hibernate
• Hibernate Architecture
• Hibernate project
• Hibernate with Annotations
• DAO Design Pattern in Java
For more information, visit this link:
https://www.mindsmapped.com/courses/software-development/learn-hibernate-fundamentals-from-scratch/
In this core java training session, you will learn JDBC Cont. Topics covered in this session are:
• JDBC Continued
• Introduction to Java Enterprise Edition (Java EE)
For more information about this course visit on this link: https://www.mindsmapped.com/courses/software-development/learn-java-fundamentals-hands-on-training-on-core-java-concepts/
In this core java training session, you will learn Examples of File IO &
Introduction to JDBC. Topics covered in this session are:
• File IO Continued
• Intro to JDBC (Java Database Connectivity)
For more information about this course visit on this link: https://www.mindsmapped.com/courses/software-development/learn-java-fundamentals-hands-on-training-on-core-java-concepts/
In this core java training session, you will learn Java IO – Files, Streams and
Object Serialization. Topics covered in this session are:
• Java IO
• Files
• Streams
• Byte-based
• Character-based
• Object Serialization
For more information about this course visit on this link: https://www.mindsmapped.com/courses/software-development/learn-java-fundamentals-hands-on-training-on-core-java-concepts/
In this core java training session, you will learn Inner Classes. Topics covered in this session are:
• Inner Classes
• Method-local Inner Class
• Anonymous Inner Class
• Static Nested Inner Class
For more information about this course visit on this link: https://www.mindsmapped.com/courses/software-development/learn-java-fundamentals-hands-on-training-on-core-java-concepts/
In this core java training session, you will learn Collections - Maps. Topics covered in this session are:
• Collections – Maps
• Map Interface
• Map methods
• Mapuse
• Hashmap
• Treemap
• Utilities
For more information about this course visit on this link: https://www.mindsmapped.com/courses/software-development/learn-java-fundamentals-hands-on-training-on-core-java-concepts/
In this core java training session, you will learn Java Review. Topics covered in this session are:
• How to prepare for a typical Java interview?
• Typical interview questions…
For more information about this course visit on this link: https://www.mindsmapped.com/courses/software-development/learn-java-fundamentals-hands-on-training-on-core-java-concepts/
Review Session and Attending Java Interviews Hitesh-Java
In this core java training session, you will learn Java Review. Topics covered in this session are:
• How to prepare for a typical Java interview?
• Typical interview questions…
For more information about this course visit on this link: https://www.mindsmapped.com/courses/software-development/learn-java-fundamentals-hands-on-training-on-core-java-concepts/
In this core java training session, you will learn Collections – Sorting, Comparing. Topics covered in this session are:
• Recap of Arrays, ArrayLists
• Basically, there can be 2 operations that you would want to perform on Arrays/ArrayLists.. (and maybe, other collections)
• Search: Override equals() and hashCode().
• Sort: provide comparison logic – Two ways
• Comparable interface
• Comparator interface
For more information about this course visit on this link: https://www.mindsmapped.com/courses/software-development/learn-java-fundamentals-hands-on-training-on-core-java-concepts/
In this core java training session, you will learn Collections. Topics covered in this session are:
• Recap of Arrays
• Introduction to Collections API
• Lists – ArrayList, Vector, LinkedList
For more information about this course visit on this link: https://www.mindsmapped.com/courses/software-development/learn-java-fundamentals-hands-on-training-on-core-java-concepts/
In this core java training session, you will learn Object Class. Topics covered in this session are:
• Object Class
• toString()
• equals()
• Hashing
• hashCode()
For more information about this course visit on this link: https://www.mindsmapped.com/courses/software-development/learn-java-fundamentals-hands-on-training-on-core-java-concepts/
Transcript: Selling digital books in 2024: Insights from industry leaders - T...BookNet Canada
The publishing industry has been selling digital audiobooks and ebooks for over a decade and has found its groove. What’s changed? What has stayed the same? Where do we go from here? Join a group of leading sales peers from across the industry for a conversation about the lessons learned since the popularization of digital books, best practices, digital book supply chain management, and more.
Link to video recording: https://bnctechforum.ca/sessions/selling-digital-books-in-2024-insights-from-industry-leaders/
Presented by BookNet Canada on May 28, 2024, with support from the Department of Canadian Heritage.
Software Delivery At the Speed of AI: Inflectra Invests In AI-Powered QualityInflectra
In this insightful webinar, Inflectra explores how artificial intelligence (AI) is transforming software development and testing. Discover how AI-powered tools are revolutionizing every stage of the software development lifecycle (SDLC), from design and prototyping to testing, deployment, and monitoring.
Learn about:
• The Future of Testing: How AI is shifting testing towards verification, analysis, and higher-level skills, while reducing repetitive tasks.
• Test Automation: How AI-powered test case generation, optimization, and self-healing tests are making testing more efficient and effective.
• Visual Testing: Explore the emerging capabilities of AI in visual testing and how it's set to revolutionize UI verification.
• Inflectra's AI Solutions: See demonstrations of Inflectra's cutting-edge AI tools like the ChatGPT plugin and Azure Open AI platform, designed to streamline your testing process.
Whether you're a developer, tester, or QA professional, this webinar will give you valuable insights into how AI is shaping the future of software delivery.
The Art of the Pitch: WordPress Relationships and SalesLaura Byrne
Clients don’t know what they don’t know. What web solutions are right for them? How does WordPress come into the picture? How do you make sure you understand scope and timeline? What do you do if sometime changes?
All these questions and more will be explored as we talk about matching clients’ needs with what your agency offers without pulling teeth or pulling your hair out. Practical tips, and strategies for successful relationship building that leads to closing the deal.
Kubernetes & AI - Beauty and the Beast !?! @KCD Istanbul 2024Tobias Schneck
As AI technology is pushing into IT I was wondering myself, as an “infrastructure container kubernetes guy”, how get this fancy AI technology get managed from an infrastructure operational view? Is it possible to apply our lovely cloud native principals as well? What benefit’s both technologies could bring to each other?
Let me take this questions and provide you a short journey through existing deployment models and use cases for AI software. On practical examples, we discuss what cloud/on-premise strategy we may need for applying it to our own infrastructure to get it to work from an enterprise perspective. I want to give an overview about infrastructure requirements and technologies, what could be beneficial or limiting your AI use cases in an enterprise environment. An interactive Demo will give you some insides, what approaches I got already working for real.
Let's dive deeper into the world of ODC! Ricardo Alves (OutSystems) will join us to tell all about the new Data Fabric. After that, Sezen de Bruijn (OutSystems) will get into the details on how to best design a sturdy architecture within ODC.
Neuro-symbolic is not enough, we need neuro-*semantic*Frank van Harmelen
Neuro-symbolic (NeSy) AI is on the rise. However, simply machine learning on just any symbolic structure is not sufficient to really harvest the gains of NeSy. These will only be gained when the symbolic structures have an actual semantics. I give an operational definition of semantics as “predictable inference”.
All of this illustrated with link prediction over knowledge graphs, but the argument is general.
Search and Society: Reimagining Information Access for Radical FuturesBhaskar Mitra
The field of Information retrieval (IR) is currently undergoing a transformative shift, at least partly due to the emerging applications of generative AI to information access. In this talk, we will deliberate on the sociotechnical implications of generative AI for information access. We will argue that there is both a critical necessity and an exciting opportunity for the IR community to re-center our research agendas on societal needs while dismantling the artificial separation between the work on fairness, accountability, transparency, and ethics in IR and the rest of IR research. Instead of adopting a reactionary strategy of trying to mitigate potential social harms from emerging technologies, the community should aim to proactively set the research agenda for the kinds of systems we should build inspired by diverse explicitly stated sociotechnical imaginaries. The sociotechnical imaginaries that underpin the design and development of information access technologies needs to be explicitly articulated, and we need to develop theories of change in context of these diverse perspectives. Our guiding future imaginaries must be informed by other academic fields, such as democratic theory and critical theory, and should be co-developed with social science scholars, legal scholars, civil rights and social justice activists, and artists, among others.
DevOps and Testing slides at DASA ConnectKari Kakkonen
My and Rik Marselis slides at 30.5.2024 DASA Connect conference. We discuss about what is testing, then what is agile testing and finally what is Testing in DevOps. Finally we had lovely workshop with the participants trying to find out different ways to think about quality and testing in different parts of the DevOps infinity loop.
2. Page 1Classification: Restricted
Agenda…
• Deep dive into coding OOP with Java… with practical examples.
• How to create a class
• How to create objects
• How to create instance variables
• How to create class variables
• Constructors
3. Java & JEE Training
Object Oriented Programming with Java
- Basic Class Demo
4. Page 3Classification: Restricted
Naming Conventions
Name Convention
class name should start with uppercase letter and be a noun e.g.
String, Color, Button, System, Thread etc.
interface name should start with uppercase letter and be an adjective
e.g. Runnable, Remote, ActionListener etc.
method name should start with lowercase letter and be a verb e.g.
actionPerformed(), main(), print(), println() etc.
variable name should start with lowercase letter e.g. firstName,
orderNumber etc.
package name should be in lowercase letter e.g. java, lang, sql, util
etc.
constants name should be in uppercase letter. e.g. RED, YELLOW,
MAX_PRIORITY etc.
5. Page 4Classification: Restricted
Object and Class in Java - Demo
A basic example of a class:
class Student1{
int id;//data member (also instance variable)
String name;//data member(also instance variable)
public static void main(String args[]){
Student1 s1=new Student1();//creating an object of Student
System.out.println(s1.id);
System.out.println(s1.name);
}
}
6. Page 5Classification: Restricted
Another Example of Objects and Classes in Java
class Student2{
int rollno;
String name;
void insertRecord(int r, String n){ //method
rollno=r;
name=n;
}
void displayInformation(){System.out.println(rollno+" "+name);}//method
public static void main(String args[]){
Student2 s1=new Student2();
Student2 s2=new Student2();
s1.insertRecord(111,"Karan");
s2.insertRecord(222,"Aryan");
s1.displayInformation();
s2.displayInformation();
}
}
9. Page 8Classification: Restricted
Method Overloading
• If a class have multiple methods by same name but different parameters.
• Advantage: Increases readability of the program.
• Two ways:
oBy changing number of arguments
oBy changing the data type
10. Page 9Classification: Restricted
Method Overloading: Changing number of arguments
class Calculation{
void sum(int a,int b){System.out.println(a+b);}
void sum(int a,int b,int c){System.out.println(a+b+c);}
public static void main(String args[]){
Calculation obj=new Calculation();
obj.sum(10,10,10);
obj.sum(20,20);
}
}
11. Page 10Classification: Restricted
Method overloading: Changing data type of argument
class Calculation2{
void sum(int a,int b){System.out.println(a+b);}
void sum(double a,double b){System.out.println(a+b);}
public static void main(String args[]){
Calculation2 obj=new Calculation2();
obj.sum(10.5,10.5);
obj.sum(20,20);
}
}
12. Page 11Classification: Restricted
Method overloading: Can it be done by
changing return type of methods?
class Calculation3{
int sum(int a,int b){System.out.println(a+b);}
double sum(int a,int b){System.out.println(a+b);}
public static void main(String args[]){
Calculation3 obj=new Calculation3();
int result=obj.sum(20,20);
/* Compile Time Error; Here how can java determine which
sum() method should be called */
}
}
//
13. Page 12Classification: Restricted
Method Overloading: Can we overload main() method?
class Overloading1{
public static void main(int a){
System.out.println(a);
}
public static void main(String args[]){
System.out.println("main() method invoked");
main(10);
}
}
14. Page 13Classification: Restricted
Method Overloading and Type Promotion
One type is promoted to another implicitly if no matching datatype is found
class OverloadingCalculation1{
void sum(int a,long b){System.out.println(a+b);}
void sum(int a,int b,int c){System.out.println(a+b+c);}
public static void main(String args[]){
OverloadingCalculation1 obj=new OverloadingCalculation1();
obj.sum(20,20);//now second int literal will be promoted to long
obj.sum(20,20,20);
}
}
16. Page 15Classification: Restricted
Constructors
• Constructor in java is a special type of method that is used to initialize the
object.
• Java constructor is invoked at the time of object creation.
• Two rules:
oConstructor name must be same as its class name
oConstructor must have no explicit return type
oIf there is no constructor in a class, compiler automatically creates a
default constructor.
18. Page 17Classification: Restricted
Example of default constructor that displays the default values
class Student3{
int id;
String name;
void display(){
System.out.println(id+" "+name);
}
public static void main(String args[]){
Student3 s1=new Student3();
Student3 s2=new Student3();
s1.display();
s2.display();
}
}
19. Page 18Classification: Restricted
Example of parameterized constructor
class Student4{
int id;
String name;
Student4(int i,String n){ //Paremeterized Constructor
id = i;
name = n;
}
void display(){System.out.println(id+" "+name);}
public static void main(String args[]){
Student4 s1 = new Student4(111,"Karan");
Student4 s2 = new Student4(222,"Aryan");
s1.display();
s2.display();
}
}
20. Page 19Classification: Restricted
Example of Constructor Overloading
class Student5{
int id;
String name;
int age;
Student5(int i,String n){
id = i;
name = n;
}
Student5(int i,String n,int a){
id = i;
name = n;
age=a;
}
void display(){System.out.println(id+" "+name+" "+age);}
public static void main(String args[]){
Student5 s1 = new Student5(111,"Karan");
Student5 s2 = new Student5(222,"Aryan",25);
s1.display();
s2.display();
}
}
21. Page 20Classification: Restricted
Constructor vs Method
Java Constructor Java Method
Constructor is used to initialize the
state of an object.
Method is used to expose behaviour
of an object.
Constructor must not have return
type.
Method must have return type.
Constructor is invoked implicitly. Method is invoked explicitly.
The java compiler provides a default
constructor if you don't have any
constructor.
Method is not provided by compiler
in any case.
Constructor name must be same as
the class name.
Method name may or may not be
same as class name.
22. Page 21Classification: Restricted
Constructor Example: Used for cloning
class Student6{
int id;
String name;
Student6(int i, String n){
id = i;
name = n;
}
Student6(Student6 s){
id = s.id;
name =s.name;
}
void display(){System.out.println(id+" "+name);}
public static void main(String args[]){
Student6 s1 = new Student6(111,"Karan");
Student6 s2 = new Student6(s1);
s1.display();
s2.display();
}
}
25. Page 24Classification: Restricted
Java “Static”
• The static keyword in java is used for memory management mainly.
• We can apply java static keyword with variables, methods, blocks and
nested class.
• The static keyword belongs to the class than instance of the class.
• The static can be:
ovariable (also known as class variable)
omethod (also known as class method)
oblock
onested class
26. Page 25Classification: Restricted
Java Static Variable
• If you declare any variable as static, it is known static variable.
• The static variable can be used to refer the common property of all objects
(that is not unique for each object) e.g. company name of employees,
college name of students etc.
• The static variable gets memory only once in class area at the time of class
loading.
• Advantage:
It makes your program memory efficient
30. Page 29Classification: Restricted
Example: Counter with static variable
class Counter2{
static int count=0;//will get memory only once and retain its value
Counter2(){
count++;
System.out.println(count);
}
public static void main(String args[]){
Counter2 c1=new Counter2();
Counter2 c2=new Counter2();
Counter2 c3=new Counter2();
}
}
31. Page 30Classification: Restricted
Java Static Method
• A static method belongs to the class rather than object of a class.
• A static method can be invoked without the need for creating an instance
of a class.
• static method can access static data member and can change the value of
it.
• There are two main restrictions for the static method. They are:
oThe static method can not use non static data member or call non-static
method directly.
othis and super cannot be used in static context.
32. Page 31Classification: Restricted
Static Method Example
class Student9{
int rollno;
String name;
static String college = "ITS";
static void change(){
college = "BBDIT";
}
Student9(int r, String n){
rollno = r;
name = n;
}
void display (){System.out.println(rollno+" "+name+" "+college);}
public static void main(String args[]){
Student9.change();
Student9 s1 = new Student9 (111,"Karan");
Student9 s2 = new Student9 (222,"Aryan");
Student9 s3 = new Student9 (333,"Sonoo");
s1.display();
s2.display();
s3.display();
}
}
33. Page 32Classification: Restricted
Example of static method that performs normal calculation
//Program to get cube of a given number by static method
class Calculate{
static int cube(int x){
return x*x*x;
}
public static void main(String args[]){
int result=Calculate.cube(5);
System.out.println(result);
}
}
36. Page 35Classification: Restricted
Java Static Block
• Is used to initialize the static data member.
• It is executed before main method at the time of classloading.
class A2{
static{System.out.println("static block is invoked");}
public static void main(String args[]){
System.out.println("Hello main");
}
}
37. Page 36Classification: Restricted
“this” keyword
• In java, this is a reference variable that refers to the current object.
• Uses:
• this keyword can be used to refer current class instance variable.
• this() can be used to invoke current class constructor.
• this keyword can be used to invoke current class method (implicitly)
• this can be passed as an argument in the method call.
• this can be passed as argument in the constructor call.
• this keyword can also be used to return the current class instance.
38. Page 37Classification: Restricted
What’s the problem with the below code?
class Student10{
int id;
String name;
Student10(int id,String name){
id = id;
name = name;
}
void display(){System.out.println(id+" "+name);}
public static void main(String args[]){
Student10 s1 = new Student10(111,"Karan");
Student10 s2 = new Student10(321,"Aryan");
s1.display();
s2.display();
}
}
39. Page 38Classification: Restricted
Solution:
//example of this keyword
class Student11{
int id;
String name;
Student11(int id,String name){
this.id = id;
this.name = name;
}
void display(){System.out.println(id+" "+name);}
public static void main(String args[]){
Student11 s1 = new Student11(111,"Karan");
Student11 s2 = new Student11(222,"Aryan");
s1.display();
s2.display();
}
}
Note: If local variables(formal arguments) and instance variables are different, there is no need to use this
keyword like in the following program:
40. Page 39Classification: Restricted
this() for invoking current class constructor: Constructor Chaining
//Program of this() constructor call (constructor chaining)
class Student13{
int id;
String name;
Student13(){System.out.println("default constructor is invoked");}
Student13(int id,String name){
this ();//it is used to invoked current class constructor.
this.id = id;
this.name = name;
}
void display(){System.out.println(id+" "+name);}
public static void main(String args[]){
Student13 e1 = new Student13(111,"karan");
Student13 e2 = new Student13(222,"Aryan");
e1.display();
e2.display();
}
}
Rule: Call to this() must be the first statement in constructor.
41. Page 40Classification: Restricted
this keyword can be used to invoke current class method (explicitly)
class S{
void m(){
System.out.println("method is invoked");
}
void n(){
this.m();//no need because compiler does it for you.
}
void p(){
n();//complier will add this to invoke n() method as this.n()
}
public static void main(String args[]){
S s1 = new S();
s1.p();
}
}
42. Page 41Classification: Restricted
this keyword can be passed as an argument in the method
class S2{
void m(S2 obj){
System.out.println("method is invoked");
}
void p(){
m(this);
}
public static void main(String args[]){
S2 s1 = new S2();
s1.p();
}
}
43. Page 42Classification: Restricted
What is the output? What does the below code do?
class A5{
void m(){
System.out.println(this);//prints same reference ID
}
public static void main(String args[]){
A5 obj=new A5();
System.out.println(obj);//prints the reference ID
obj.m();
}
}
44. Page 43Classification: Restricted
Topics to be covered in next session
• Review of last class concepts
• Types of Inheritance and a look at Aggregation
• Polymorphism
• Method overloading
• Method overriding