This document discusses inheritance and GUI components in Java. It begins by reviewing how to create basic GUI frames and components using classes like JFrame and JOptionPane. It then explains the concepts of inheritance, where a subclass inherits attributes and methods from its superclass. Regarding GUIs, the document shows how custom GUI frames can be created by extending the JFrame class and overriding its methods. This allows creating specialized frame classes with customized functionality and properties.
This document provides an overview of object-oriented programming concepts in Java including classes, objects, attributes, and methods. It discusses how classes define templates for objects and how objects are instances of classes. Examples are given of declaring a class for a car with attributes like make and speed, and methods like accelerate and turn. The document also covers creating objects from classes in code, and accessing object attributes and methods. Finally, it briefly introduces some standard Java classes like Math that are commonly used.
This document provides an overview of several Java standard classes including Date, SimpleDateFormat, Scanner, Math, and DecimalFormat. It discusses how to create objects from these classes, commonly used methods, and examples of how to incorporate them into programs. For Date, it demonstrates getting the current date, comparing dates, and formatting dates. For Scanner, it shows reading user input. For Math, it lists common mathematical methods. For DecimalFormat, it demonstrates formatting numbers to a specified number of decimal places.
1) Encapsulation means keeping variables and methods together inside a class. This allows functionality to be embedded within objects.
2) Inheritance allows a child class to extend a parent class. The child class inherits features from the parent class but can also define new features.
3) Encapsulation and inheritance are key aspects of object-oriented programming that allow for code reuse and organization. Encapsulation groups related data and behaviors within a class while inheritance establishes a parent-child relationship between classes.
This document provides an overview of object-oriented programming (OOP) concepts in Java, including classes, objects, inheritance, encapsulation, polymorphism, and dynamic binding. It explains the basic structure of a Java class, how to define methods and variables, and how to instantiate objects from classes. The document also discusses constructors and how to use inheritance to extend existing classes.
Wrapper classes allow primitive data types like int and double to be used as objects. Each primitive type has a corresponding wrapper class like Integer and Double. Wrapper classes allow primitive values to be passed by reference rather than by value. GUIs can be created using Swing components like JFrame for windows and JOptionPane for simple input/output dialogs. Components are added to the content pane of the JFrame to build the GUI interface.
Classes allow the creation of user-defined data types through the grouping of related properties and behaviors. They contain members like variables and methods that can be declared as private, protected, public or static. Constructors initialize new class objects, while finalizers run before objects are destroyed. The toString method returns a string representation of an object. Abstract data types specify logical properties without implementation details. An example program designs classes for a candy machine application that displays products, accepts selections and payments, and dispenses items.
Object oriented programming involves modeling real-world entities as objects that encapsulate both data and behavior. Programmers define classes that specify the attributes and methods of these objects. This is a different approach than traditional procedural programming, as it focuses on objects rather than functions.
Object oriented programming involves modeling real-world entities as objects that encapsulate both data and behavior. Programmers define classes that specify the attributes and methods of these objects. This is a different approach than traditional procedural programming, as it focuses on objects rather than functions.
This document provides an overview of object-oriented programming concepts in Java including classes, objects, attributes, and methods. It discusses how classes define templates for objects and how objects are instances of classes. Examples are given of declaring a class for a car with attributes like make and speed, and methods like accelerate and turn. The document also covers creating objects from classes in code, and accessing object attributes and methods. Finally, it briefly introduces some standard Java classes like Math that are commonly used.
This document provides an overview of several Java standard classes including Date, SimpleDateFormat, Scanner, Math, and DecimalFormat. It discusses how to create objects from these classes, commonly used methods, and examples of how to incorporate them into programs. For Date, it demonstrates getting the current date, comparing dates, and formatting dates. For Scanner, it shows reading user input. For Math, it lists common mathematical methods. For DecimalFormat, it demonstrates formatting numbers to a specified number of decimal places.
1) Encapsulation means keeping variables and methods together inside a class. This allows functionality to be embedded within objects.
2) Inheritance allows a child class to extend a parent class. The child class inherits features from the parent class but can also define new features.
3) Encapsulation and inheritance are key aspects of object-oriented programming that allow for code reuse and organization. Encapsulation groups related data and behaviors within a class while inheritance establishes a parent-child relationship between classes.
This document provides an overview of object-oriented programming (OOP) concepts in Java, including classes, objects, inheritance, encapsulation, polymorphism, and dynamic binding. It explains the basic structure of a Java class, how to define methods and variables, and how to instantiate objects from classes. The document also discusses constructors and how to use inheritance to extend existing classes.
Wrapper classes allow primitive data types like int and double to be used as objects. Each primitive type has a corresponding wrapper class like Integer and Double. Wrapper classes allow primitive values to be passed by reference rather than by value. GUIs can be created using Swing components like JFrame for windows and JOptionPane for simple input/output dialogs. Components are added to the content pane of the JFrame to build the GUI interface.
Classes allow the creation of user-defined data types through the grouping of related properties and behaviors. They contain members like variables and methods that can be declared as private, protected, public or static. Constructors initialize new class objects, while finalizers run before objects are destroyed. The toString method returns a string representation of an object. Abstract data types specify logical properties without implementation details. An example program designs classes for a candy machine application that displays products, accepts selections and payments, and dispenses items.
Object oriented programming involves modeling real-world entities as objects that encapsulate both data and behavior. Programmers define classes that specify the attributes and methods of these objects. This is a different approach than traditional procedural programming, as it focuses on objects rather than functions.
Object oriented programming involves modeling real-world entities as objects that encapsulate both data and behavior. Programmers define classes that specify the attributes and methods of these objects. This is a different approach than traditional procedural programming, as it focuses on objects rather than functions.
Inheritance allows classes to establish a hierarchical "is-a" relationship where subclasses inherit and extend the functionality of superclasses. A subclass inherits all fields and methods from its direct superclass and inherits from all superclasses up the class hierarchy with Object at the top. Constructors must call superclass constructors to initialize inherited fields properly. Subclasses can override methods of superclasses to provide specialized implementations while preserving the original signature. Polymorphism occurs when subclass objects are referenced by superclass references and the method invoked is based on the object's actual type. Final methods and classes prevent overriding and extension respectively.
The static keyword in Java is used for memory management and can be applied to variables, methods, blocks, and nested classes. Static variables and methods are associated with the class itself rather than with specific objects. A static variable loads into memory only once during class loading and can be accessed without creating instances of the class. Static methods can access static data members and can be called without creating object instances. Static blocks are used to initialize static variables and are executed during class loading before the main method.
The document discusses creating classes in Java. It covers:
1. Creating a class with attributes and methods, including get/set methods and constructors.
2. Using private and public access modifiers to control which parts of a class can be accessed from outside the class.
3. The principle of encapsulation, which separates the external interface of a class from its internal implementation through information hiding.
Webinar topic: Customise Odoo addons modules
Presenter: Achmad Mardiansyah
In this webinar series, We are discussing Customise Odoo addons modules
Please share your feedback or webinar ideas here: http://bit.ly/glcfeedback
Check our schedule for future events: https://www.glcnetworks.com/en/schedule/
Follow our social media for updates: Facebook, Instagram, YouTube Channel, and telegram also discord
Recording available on Youtube
https://youtu.be/lvkOxprEzi4
The document provides an overview of JavaScript design patterns including creational, structural, and behavioral patterns. It discusses common patterns like the module pattern, prototype pattern, factory pattern, decorator pattern, observer pattern, and more. Code examples are provided to demonstrate how each pattern works in JavaScript.
The document discusses object-oriented programming concepts in C++ including classes, objects, data members, member functions, access specifiers, and more. It provides examples to demonstrate defining a class with data members and member functions, declaring objects of a class, accessing class members using dot operator, passing objects to functions by value and reference, returning objects from functions, static class members, and nested classes. It also addresses scope of classes and objects, inline functions, and constant member functions.
This document provides an overview of inheritance in Java. It begins with an introduction to inheritance concepts like superclass, subclass, overriding methods, and polymorphism. It then covers deriving a subclass, including subclass fields, constructors, and methods. It discusses using subclasses and notes on this, super, and protected access. It concludes with special class types like abstract classes, which can contain abstract methods, and final classes/methods, which cannot be overridden.
This document provides an introduction to object-oriented programming concepts in Java including objects, classes, inheritance, polymorphism, and more. It defines key terms like class, object, state, behavior, identity. It also discusses the differences between objects and classes and provides examples of declaring classes and creating objects in Java. Methods, constructors, and initialization of objects are explained. Inheritance, method overriding, and polymorphism are defined along with examples.
This document summarizes key concepts in object-oriented programming (OOP) in Java, including static keyword, instance member, class member, inheritance, encapsulation, polymorphism, object, class, constructor, and more. It provides examples to illustrate static variables and methods, the this keyword, super keyword, final keyword, abstract classes vs interfaces, and method overloading as a form of compile-time polymorphism.
Here are the key points about object equality in Java:
- The == operator checks if the objects are the same instance
- The equals() method checks if the objects have the same value
- By default, equals() only returns true if comparing the same instance
- Classes should override equals() to check for value equality instead of reference equality
So in this case:
- jack1 == jack2 will print false as they are different instances
- jack1.equals(jack2) will print false by default, as equals() isn't overridden
This document provides an overview of object-oriented programming concepts in Java, including classes, objects, variables, methods, constructors, abstraction, encapsulation, inheritance, and polymorphism. It defines classes and objects, and describes how classes act as blueprints for objects. It explains the syntax for defining classes and class members like variables and methods. It also covers method overloading, different types of methods, and how constructors are used to initialize objects. The document concludes with brief explanations of abstraction, encapsulation, inheritance, and polymorphism as fundamental principles of object-oriented design.
Java Swing is a GUI widget toolkit for Java that builds upon the Abstract Window Toolkit (AWT) to provide a more sophisticated set of GUI components. It includes common widgets like buttons, text fields, labels and menus. Components in Swing are lightweight objects that can be easily rendered on screen. Containers hold and organize other components in a hierarchy. The most commonly used containers are JFrame, JPanel and JWindow. JFrame is Swing's version of a top-level window with options to close or hide. JTextField allows editing single-line text while JLabel displays read-only text. An example program demonstrates adding components like labels, text fields and buttons to a JFrame and handling button click events
Hello. Im currently working on the last section to my assignment a.pdfirshadkumar3
Hello. I\'m currently working on the last section to my assignment and I\'m running into issues.
I\'ll post a screenshot of the directions provided to us, my 5 classes, and a screenshot of my
console output. Can you help me fix my code? I don\'t know where it\'s going wrong and I can\'t
figure it out. Please leave comments on what I did wrong so I can learn from it. Thank you so
much!
Here is the instructions from the pdf for reference on what I\'m trying to accomplish.
package campus;
public class Person {
private String id;
private String lastName;
private String firstName;
public Person(String id, String last, String first)
{
this.id = id;
this.lastName = last;
this.firstName = first;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getId() {
return id;
}
public String toString()
{
return id + \": \" + firstName + \" \" + lastName;
}
}
------
---Student.java---
package campus;
public class Student extends Person {
private String major;
private int level;
private Person obj;
public Student(String id, String last, String first, String focus, int level) {
super(id, last, first);// calling parent constructor
this.major = focus;
this.level = level;
obj = new Person(id, last, first);
}
public String getMajor() {
return major;
}
public void setMajor(String major) {
this.major = major;
}
public int getLevel() {
return level;
}
public void setLevel(int level) {
this.level = level;
}
@Override
public String toString() { // override toString() method
return \"id: \" + obj.getId() + \", Name: \" + obj.getFirstName() + \" \" + obj.getLastName()
+ \", major is \"
+ this.major + \" and their level is \" + this.level;
}
}
------
---Faculty.java---
package campus;
public class Faculty extends Person {
private String dept;
private String rank;
private Person obj;
public Faculty(String id, String last, String first, String focus, int level) {
super(id, last, first);// calling parent constructor
}
public String getDept() {
return dept;
}
public void setDept(String dept) {
this.dept = dept;
}
public String getRank() {
return rank;
}
public void setRank(int level) {
this.rank = rank;
}
@Override
public String toString() { // override toString() method
return \"id: \" + obj.getId() + \", Name: \" + obj.getFirstName() + \" \" + obj.getLastName()
+ \", deptartment is \"
+ this.dept + \" and their rank is \" + this.rank;
}
}
------
---Section.java---
package campus;
public class Section {
private String id;
private Faculty instructor;
private Student[] enrolled;
private int numofEnroll;
private int capacity;
private String location;
private String time;
private String semester;
public Section(String id, Faculty instructor, int capacity, String location, String time, String
semester) {
}
public Section(String id, int capacity) {
this.id = id;
this.capacity .
The document discusses the steps to create a Java quiz application project using Java Swing and SQLite. It describes creating classes like AdminLogin, AdminPanel, Database, Question etc. to handle authentication, questions management and database operations. The project allows admins to add, delete and view questions and users, while users can attempt quizzes and view performance feedback.
Logic and Coding of Java Interfaces & Swing Applicationskjkleindorfer
The document discusses interfaces in Java. It defines interfaces as listing methods and signatures that classes implementing the interface must provide. All interface methods are public and abstract. Interfaces cannot have instance variables or static methods. The document provides an example FileHelper interface and classes that implement it. It also discusses adding components like buttons and labels to a JFrame, creating listener classes to handle events, and attaching listeners to components.
The document discusses defining classes and objects in Java. It covers defining simple classes, class elements like fields and methods, constructors, properties, static members, and using classes by creating instances and calling methods. Key points include classes define the structure of objects, constructors initialize object state, properties encapsulate fields, and static members are associated with a class not individual objects.
Inheritance, polymorphisam, abstract classes and composition)farhan amjad
The document discusses object-oriented programming concepts like inheritance, encapsulation, polymorphism and data hiding. It provides examples to explain inheritance, where a derived class inherits attributes and behaviors from a base class. Derived classes can specialize or extend the base class while reusing its code.
UNIT-2.pptx CS3391 Inheritance , types, packages and InterfacesSakkaravarthiS1
This document discusses various Java concepts including method overloading, objects as parameters, returning objects, static, nested and inner classes, inheritance basics and types, the super keyword, method overriding and dynamic method dispatch, abstract classes, final with inheritance, packages and interfaces. It provides examples and explanations of each concept.
This document discusses object placement and layout managers in GUI programming. It describes how to add objects like buttons and labels to a content pane and use different layout managers, including FlowLayout, BorderLayout, and GridLayout, to determine object positioning. It also introduces the concept of panels, which allow sectioning of a frame and the use of nested layouts.
The document discusses object-oriented programming concepts like passing objects to methods, returning objects from methods, using objects as attributes, and overloading methods. Specifically, it provides an example of creating an Equipment class with attributes like name and value, and methods to get those attributes, loan the equipment to a student, and check which student it is loaned to. It also shows adding a borrowed equipment attribute to the Student class to track equipment loans.
Inheritance allows classes to establish a hierarchical "is-a" relationship where subclasses inherit and extend the functionality of superclasses. A subclass inherits all fields and methods from its direct superclass and inherits from all superclasses up the class hierarchy with Object at the top. Constructors must call superclass constructors to initialize inherited fields properly. Subclasses can override methods of superclasses to provide specialized implementations while preserving the original signature. Polymorphism occurs when subclass objects are referenced by superclass references and the method invoked is based on the object's actual type. Final methods and classes prevent overriding and extension respectively.
The static keyword in Java is used for memory management and can be applied to variables, methods, blocks, and nested classes. Static variables and methods are associated with the class itself rather than with specific objects. A static variable loads into memory only once during class loading and can be accessed without creating instances of the class. Static methods can access static data members and can be called without creating object instances. Static blocks are used to initialize static variables and are executed during class loading before the main method.
The document discusses creating classes in Java. It covers:
1. Creating a class with attributes and methods, including get/set methods and constructors.
2. Using private and public access modifiers to control which parts of a class can be accessed from outside the class.
3. The principle of encapsulation, which separates the external interface of a class from its internal implementation through information hiding.
Webinar topic: Customise Odoo addons modules
Presenter: Achmad Mardiansyah
In this webinar series, We are discussing Customise Odoo addons modules
Please share your feedback or webinar ideas here: http://bit.ly/glcfeedback
Check our schedule for future events: https://www.glcnetworks.com/en/schedule/
Follow our social media for updates: Facebook, Instagram, YouTube Channel, and telegram also discord
Recording available on Youtube
https://youtu.be/lvkOxprEzi4
The document provides an overview of JavaScript design patterns including creational, structural, and behavioral patterns. It discusses common patterns like the module pattern, prototype pattern, factory pattern, decorator pattern, observer pattern, and more. Code examples are provided to demonstrate how each pattern works in JavaScript.
The document discusses object-oriented programming concepts in C++ including classes, objects, data members, member functions, access specifiers, and more. It provides examples to demonstrate defining a class with data members and member functions, declaring objects of a class, accessing class members using dot operator, passing objects to functions by value and reference, returning objects from functions, static class members, and nested classes. It also addresses scope of classes and objects, inline functions, and constant member functions.
This document provides an overview of inheritance in Java. It begins with an introduction to inheritance concepts like superclass, subclass, overriding methods, and polymorphism. It then covers deriving a subclass, including subclass fields, constructors, and methods. It discusses using subclasses and notes on this, super, and protected access. It concludes with special class types like abstract classes, which can contain abstract methods, and final classes/methods, which cannot be overridden.
This document provides an introduction to object-oriented programming concepts in Java including objects, classes, inheritance, polymorphism, and more. It defines key terms like class, object, state, behavior, identity. It also discusses the differences between objects and classes and provides examples of declaring classes and creating objects in Java. Methods, constructors, and initialization of objects are explained. Inheritance, method overriding, and polymorphism are defined along with examples.
This document summarizes key concepts in object-oriented programming (OOP) in Java, including static keyword, instance member, class member, inheritance, encapsulation, polymorphism, object, class, constructor, and more. It provides examples to illustrate static variables and methods, the this keyword, super keyword, final keyword, abstract classes vs interfaces, and method overloading as a form of compile-time polymorphism.
Here are the key points about object equality in Java:
- The == operator checks if the objects are the same instance
- The equals() method checks if the objects have the same value
- By default, equals() only returns true if comparing the same instance
- Classes should override equals() to check for value equality instead of reference equality
So in this case:
- jack1 == jack2 will print false as they are different instances
- jack1.equals(jack2) will print false by default, as equals() isn't overridden
This document provides an overview of object-oriented programming concepts in Java, including classes, objects, variables, methods, constructors, abstraction, encapsulation, inheritance, and polymorphism. It defines classes and objects, and describes how classes act as blueprints for objects. It explains the syntax for defining classes and class members like variables and methods. It also covers method overloading, different types of methods, and how constructors are used to initialize objects. The document concludes with brief explanations of abstraction, encapsulation, inheritance, and polymorphism as fundamental principles of object-oriented design.
Java Swing is a GUI widget toolkit for Java that builds upon the Abstract Window Toolkit (AWT) to provide a more sophisticated set of GUI components. It includes common widgets like buttons, text fields, labels and menus. Components in Swing are lightweight objects that can be easily rendered on screen. Containers hold and organize other components in a hierarchy. The most commonly used containers are JFrame, JPanel and JWindow. JFrame is Swing's version of a top-level window with options to close or hide. JTextField allows editing single-line text while JLabel displays read-only text. An example program demonstrates adding components like labels, text fields and buttons to a JFrame and handling button click events
Hello. Im currently working on the last section to my assignment a.pdfirshadkumar3
Hello. I\'m currently working on the last section to my assignment and I\'m running into issues.
I\'ll post a screenshot of the directions provided to us, my 5 classes, and a screenshot of my
console output. Can you help me fix my code? I don\'t know where it\'s going wrong and I can\'t
figure it out. Please leave comments on what I did wrong so I can learn from it. Thank you so
much!
Here is the instructions from the pdf for reference on what I\'m trying to accomplish.
package campus;
public class Person {
private String id;
private String lastName;
private String firstName;
public Person(String id, String last, String first)
{
this.id = id;
this.lastName = last;
this.firstName = first;
}
public String getLastName() {
return lastName;
}
public void setLastName(String lastName) {
this.lastName = lastName;
}
public String getFirstName() {
return firstName;
}
public void setFirstName(String firstName) {
this.firstName = firstName;
}
public String getId() {
return id;
}
public String toString()
{
return id + \": \" + firstName + \" \" + lastName;
}
}
------
---Student.java---
package campus;
public class Student extends Person {
private String major;
private int level;
private Person obj;
public Student(String id, String last, String first, String focus, int level) {
super(id, last, first);// calling parent constructor
this.major = focus;
this.level = level;
obj = new Person(id, last, first);
}
public String getMajor() {
return major;
}
public void setMajor(String major) {
this.major = major;
}
public int getLevel() {
return level;
}
public void setLevel(int level) {
this.level = level;
}
@Override
public String toString() { // override toString() method
return \"id: \" + obj.getId() + \", Name: \" + obj.getFirstName() + \" \" + obj.getLastName()
+ \", major is \"
+ this.major + \" and their level is \" + this.level;
}
}
------
---Faculty.java---
package campus;
public class Faculty extends Person {
private String dept;
private String rank;
private Person obj;
public Faculty(String id, String last, String first, String focus, int level) {
super(id, last, first);// calling parent constructor
}
public String getDept() {
return dept;
}
public void setDept(String dept) {
this.dept = dept;
}
public String getRank() {
return rank;
}
public void setRank(int level) {
this.rank = rank;
}
@Override
public String toString() { // override toString() method
return \"id: \" + obj.getId() + \", Name: \" + obj.getFirstName() + \" \" + obj.getLastName()
+ \", deptartment is \"
+ this.dept + \" and their rank is \" + this.rank;
}
}
------
---Section.java---
package campus;
public class Section {
private String id;
private Faculty instructor;
private Student[] enrolled;
private int numofEnroll;
private int capacity;
private String location;
private String time;
private String semester;
public Section(String id, Faculty instructor, int capacity, String location, String time, String
semester) {
}
public Section(String id, int capacity) {
this.id = id;
this.capacity .
The document discusses the steps to create a Java quiz application project using Java Swing and SQLite. It describes creating classes like AdminLogin, AdminPanel, Database, Question etc. to handle authentication, questions management and database operations. The project allows admins to add, delete and view questions and users, while users can attempt quizzes and view performance feedback.
Logic and Coding of Java Interfaces & Swing Applicationskjkleindorfer
The document discusses interfaces in Java. It defines interfaces as listing methods and signatures that classes implementing the interface must provide. All interface methods are public and abstract. Interfaces cannot have instance variables or static methods. The document provides an example FileHelper interface and classes that implement it. It also discusses adding components like buttons and labels to a JFrame, creating listener classes to handle events, and attaching listeners to components.
The document discusses defining classes and objects in Java. It covers defining simple classes, class elements like fields and methods, constructors, properties, static members, and using classes by creating instances and calling methods. Key points include classes define the structure of objects, constructors initialize object state, properties encapsulate fields, and static members are associated with a class not individual objects.
Inheritance, polymorphisam, abstract classes and composition)farhan amjad
The document discusses object-oriented programming concepts like inheritance, encapsulation, polymorphism and data hiding. It provides examples to explain inheritance, where a derived class inherits attributes and behaviors from a base class. Derived classes can specialize or extend the base class while reusing its code.
UNIT-2.pptx CS3391 Inheritance , types, packages and InterfacesSakkaravarthiS1
This document discusses various Java concepts including method overloading, objects as parameters, returning objects, static, nested and inner classes, inheritance basics and types, the super keyword, method overriding and dynamic method dispatch, abstract classes, final with inheritance, packages and interfaces. It provides examples and explanations of each concept.
This document discusses object placement and layout managers in GUI programming. It describes how to add objects like buttons and labels to a content pane and use different layout managers, including FlowLayout, BorderLayout, and GridLayout, to determine object positioning. It also introduces the concept of panels, which allow sectioning of a frame and the use of nested layouts.
The document discusses object-oriented programming concepts like passing objects to methods, returning objects from methods, using objects as attributes, and overloading methods. Specifically, it provides an example of creating an Equipment class with attributes like name and value, and methods to get those attributes, loan the equipment to a student, and check which student it is loaned to. It also shows adding a borrowed equipment attribute to the Student class to track equipment loans.
This document discusses file handling in Java. It covers creating File objects to represent files and directories, and using streams for low-level and high-level file input and output of primitive data types, text, and objects. Methods like exists(), list(), isFile() are used to check files. The FileChooser class provides a GUI to select files. Streams like FileOutputStream, FileInputStream, PrintWriter, Scanner facilitate reading and writing files. Object streams allow writing and reading objects to files.
This document discusses event handling in Java GUI programming. It explains that GUI components like buttons and text boxes generate events like clicks and key presses. Event listeners need to be created to handle these events. The ActionListener interface is used to create classes that listen for action events. There are four ways to implement an action listener: 1) create a separate listener class, 2) make the GUI class itself the listener, 3) create a nested listener class, 4) use an anonymous inner class. The event source and event object can be used to determine which component generated the event. Multiple listeners can be used to handle different event sources.
This document discusses error handling in programs. It explains that exceptions are runtime errors that occur during program execution. When an exception occurs, it is thrown. Code can be written to catch exceptions using try-catch blocks. Different types of exceptions that may occur are discussed, along with how to define and throw custom exceptions. Finally, the document touches on exception propagation through method calls and the use of assertions to check conditions.
The document summarizes key concepts about strings and regular expressions in Java. It discusses that strings are immutable sequences of characters represented by the String class, and how to manipulate strings. It also covers that regular expressions provide a concise way to match patterns in strings using special characters. Finally, it notes that the StringBuffer and StringBuilder classes allow mutable string operations by modifying objects instead of creating new String objects.
This lecture covered the steps involved in solving a programming problem: problem identification, analysis, program design, implementation, testing, and documentation. It then discussed some key concepts for moving from C to Java, including variables, operators, control structures like if/else statements and loops, and arrays. The document provided examples and explanations of these concepts.
Discover the latest insights on Data Driven Maintenance with our comprehensive webinar presentation. Learn about traditional maintenance challenges, the right approach to utilizing data, and the benefits of adopting a Data Driven Maintenance strategy. Explore real-world examples, industry best practices, and innovative solutions like FMECA and the D3M model. This presentation, led by expert Jules Oudmans, is essential for asset owners looking to optimize their maintenance processes and leverage digital technologies for improved efficiency and performance. Download now to stay ahead in the evolving maintenance landscape.
Null Bangalore | Pentesters Approach to AWS IAMDivyanshu
#Abstract:
- Learn more about the real-world methods for auditing AWS IAM (Identity and Access Management) as a pentester. So let us proceed with a brief discussion of IAM as well as some typical misconfigurations and their potential exploits in order to reinforce the understanding of IAM security best practices.
- Gain actionable insights into AWS IAM policies and roles, using hands on approach.
#Prerequisites:
- Basic understanding of AWS services and architecture
- Familiarity with cloud security concepts
- Experience using the AWS Management Console or AWS CLI.
- For hands on lab create account on [killercoda.com](https://killercoda.com/cloudsecurity-scenario/)
# Scenario Covered:
- Basics of IAM in AWS
- Implementing IAM Policies with Least Privilege to Manage S3 Bucket
- Objective: Create an S3 bucket with least privilege IAM policy and validate access.
- Steps:
- Create S3 bucket.
- Attach least privilege policy to IAM user.
- Validate access.
- Exploiting IAM PassRole Misconfiguration
-Allows a user to pass a specific IAM role to an AWS service (ec2), typically used for service access delegation. Then exploit PassRole Misconfiguration granting unauthorized access to sensitive resources.
- Objective: Demonstrate how a PassRole misconfiguration can grant unauthorized access.
- Steps:
- Allow user to pass IAM role to EC2.
- Exploit misconfiguration for unauthorized access.
- Access sensitive resources.
- Exploiting IAM AssumeRole Misconfiguration with Overly Permissive Role
- An overly permissive IAM role configuration can lead to privilege escalation by creating a role with administrative privileges and allow a user to assume this role.
- Objective: Show how overly permissive IAM roles can lead to privilege escalation.
- Steps:
- Create role with administrative privileges.
- Allow user to assume the role.
- Perform administrative actions.
- Differentiation between PassRole vs AssumeRole
Try at [killercoda.com](https://killercoda.com/cloudsecurity-scenario/)
Advanced control scheme of doubly fed induction generator for wind turbine us...IJECEIAES
This paper describes a speed control device for generating electrical energy on an electricity network based on the doubly fed induction generator (DFIG) used for wind power conversion systems. At first, a double-fed induction generator model was constructed. A control law is formulated to govern the flow of energy between the stator of a DFIG and the energy network using three types of controllers: proportional integral (PI), sliding mode controller (SMC) and second order sliding mode controller (SOSMC). Their different results in terms of power reference tracking, reaction to unexpected speed fluctuations, sensitivity to perturbations, and resilience against machine parameter alterations are compared. MATLAB/Simulink was used to conduct the simulations for the preceding study. Multiple simulations have shown very satisfying results, and the investigations demonstrate the efficacy and power-enhancing capabilities of the suggested control system.
Design and optimization of ion propulsion dronebjmsejournal
Electric propulsion technology is widely used in many kinds of vehicles in recent years, and aircrafts are no exception. Technically, UAVs are electrically propelled but tend to produce a significant amount of noise and vibrations. Ion propulsion technology for drones is a potential solution to this problem. Ion propulsion technology is proven to be feasible in the earth’s atmosphere. The study presented in this article shows the design of EHD thrusters and power supply for ion propulsion drones along with performance optimization of high-voltage power supply for endurance in earth’s atmosphere.
Embedded machine learning-based road conditions and driving behavior monitoringIJECEIAES
Car accident rates have increased in recent years, resulting in losses in human lives, properties, and other financial costs. An embedded machine learning-based system is developed to address this critical issue. The system can monitor road conditions, detect driving patterns, and identify aggressive driving behaviors. The system is based on neural networks trained on a comprehensive dataset of driving events, driving styles, and road conditions. The system effectively detects potential risks and helps mitigate the frequency and impact of accidents. The primary goal is to ensure the safety of drivers and vehicles. Collecting data involved gathering information on three key road events: normal street and normal drive, speed bumps, circular yellow speed bumps, and three aggressive driving actions: sudden start, sudden stop, and sudden entry. The gathered data is processed and analyzed using a machine learning system designed for limited power and memory devices. The developed system resulted in 91.9% accuracy, 93.6% precision, and 92% recall. The achieved inference time on an Arduino Nano 33 BLE Sense with a 32-bit CPU running at 64 MHz is 34 ms and requires 2.6 kB peak RAM and 139.9 kB program flash memory, making it suitable for resource-constrained embedded systems.
3. Plan
▪ Review:
– Created a frame – JFrame class
JFrame jFrame = new JFrame();
jFrame.setTitle("GUIs are awesome!");
jFrame.setSize(400,300);
jFrame.setVisible(true);
jFrame.setDefaultCloseOperation(jFrame.EXIT_ON_CLOSE);
4. Plan
▪ Review:
– Created a frame – JFrame class
– Accessed the content pane of the frame – Container class
Container CP = jFrame.getContentPane();
5. Plan
▪ Review:
– Created a frame – JFrame class
– Accessed the content pane of the frame – Container class
– Created a pop-up window to give message to the user –
JOptionPane class
JOptionPane.showMessageDialog(jFrame, "Java is so much fun!");
JOptionPane.showMessageDialog(null, "Java is so much fun!");
6. Plan
▪ Review:
– Created a frame – JFrame class
– Accessed the content pane of the frame – Container class
– Created a pop-up window to give message to the user –
JOptionPane class
– Created a pop-up window to get data from the user -
JOptionPane
String s = JOptionPane.showInputDialog(jFrame, "What year were
you born in?");
int i = Integer.parseInt(s);
7. Plan
▪ Review:
– Created a frame – JFrame class
– Accessed the content pane of the frame – Container class
– Created a pop-up window to give message to the user –
JOptionPane class
– Created a pop-up window to get data from the user –
JOptionPane
▪ Look at components that we can add to the content
pane: JButton, JLabel, JTextField…
▪ Inheritance and Interfaces
9. GUIS
▪ Many different types of GUI objects
▪ https://web.mit.edu/6.005/www/sp14/psets/ps4/java-
6-tutorial/components.html - good reference
10. GUI components
Pushbutton.
▪ JButton – from the javax.swing package
▪ The text passed to the constructor is the text inside the
button.
▪ Also generates an action event – will get to later.
JButton okButton = new JButton("OK");
JButton cancelButton = new JButton("Cancel");
JButton acceptButton = new JButton("Accept", acceptIcon);
Name of the button Text on the button
11. GUI components
Text, images
▪ JLabel – from the javax.swing package
▪ The text passed to the constructor is the text inside the
Label.
▪ Can also specify an ImageIcon object which can contain
an image.
▪ No action event.
JLabel myText = new JLabel("Welcome to my program!");
12. GUI components
Images
▪ ImageIcon – from the java.swing package
▪ Used to hold an image.
▪ Can then be passed to constructor of JLabel or JButton
to actually show the image.
▪ No action event.
ImageIcon myIm = new ImageIcon("SpongeBob.jpg");
JLabel myLabel = new JLabel(myIm);
13. GUI components
Text input
▪ JTextField – from the java.swing package
▪ Allows user to enter a line of text.
▪ Constructor: initial text, the width in characters or both
▪ Has action event when user hits Enter key while it is active
(has blinking vertical line)
JTextField myTF = new JTextField();
JTextField myTF = new JTextField("Please enter your text here");
JTextField myTF = new JTextField("Please enter your text here", 40);
14. GUI components
Text input
▪ JTextArea – from the java.swing package
▪ Allows user to enter multiple lines of text.
▪ Constructor: Default text, rows and width
▪ Set the size of the object:
JTextArea myTA = new JTextArea();
JTextArea myTA = new JTextArea("Please enter your text here");
JTextArea myTA = new JTextArea("Please enter your text here", 5 , 30);
myTA.setColumns(30);
myTA.setRows(10);
15. GUI components
Drop down box
▪ JComboBox – from the java.swing package
▪ Gives the user options that they can choose from a
drop down box.
▪ Constructor: String array of choices
▪ Can also set the top box to be editable or not.
String[] times = {"10:00", "10:30", "11:00", "11:30", "12:00"};
JComboBox myCB = new JComboBox(times);
myCB.setEditable(true);
17. Inheritance
▪ In order to understand some GUI concepts, we have to
look at some inheritance concepts.
▪ Inheritance is not part of the syllabus of this course and
it will not be directly examined.
▪ But you need to understand it in order to understand
some GUI concepts.
18. Inheritance
▪ Let’s imagine we’ve created a class called Student
public class Student {
String name;
long studentNo;
int YearOfStudy;
Student(){
System.out.println("Student constructor.");
}
void MethodA() {
System.out.println("MethodA from Student.");
}
}
19. Inheritance
▪ Let’s imagine we’ve created a class called Student
▪ Now lets imagine that we want to make some other
classes based on this class:
– eg. PGStudent or UGStudent or PTstudent
▪ These classes will have a lot in common with Student
but they will have things that are unique to those
classes as well.
20. Inheritance
▪ We can create a class from
another class.
▪ We use the keyword:
extends
public class UGStudent extends Student{
String[] ListOfCourses;
float[] ListOfMarks;
float ReturnAveMark() {...}
}
public class PGStudent extends Student {
String Supervisor;
String DegreeType;
void SubmitThesis() {}
}
Inheritance
One class acquires the
members of another
class.
21. Inheritance
▪ The class we are inheriting from is called the superclass.
▪ The class that inherits is called the subclass.
Student
UGStudent PGStudent
Superclass
Subclass
22. Inheritance
▪ We can build a hierarchy of classes:
UniversityMember
Staff
Administrative
Academic
Technical
Student
UGStudent PGStudent
23. Inheritance
▪ Subclasses inherit the attributes and methods of the
superclasses
▪ Objects created from subclasses will have the attributes
and methods of the superclasses.
▪ They can then add their own attributes and methods.
24. Inheritance
public class Student {
String name;
long studentNo;
int YearOfStudy;
Student(){...}
void MethodA() {...}
}
public class UGStudent extends Student{
String[] ListOfCourses;
float[] ListOfMarks;
float ReturnAveMark() {...}
}
25. Inheritance
public class Student {
String name;
long studentNo;
int YearOfStudy;
Student(){...}
void MethodA() {...}
}
public class UGStudent extends Student{
String[] ListOfCourses;
float[] ListOfMarks;
float ReturnAveMark() {...}
}
This code isn’t
really here, but
these members
of Student are
available to
UGStudent.
26. Inheritance
▪ So if we have: public class UGStudent extends Student{
String[] ListOfCourses;
float[] ListOfMarks;
float ReturnAveMark() {...}
}
public class Student {
String name;
long studentNo;
int YearOfStudy;
Student(){
System.out.println("Student constructor.");
}
void MethodA() {
System.out.println("MethodA from Student.");
}
}
27. Inheritance
▪ Then in the main class, we can say:
PGStudent a = new PGStudent();
a.MethodA();
▪ Calling a method defined in the superclass from an object of the
subclass.
▪ The methods and attributes of the superclass are automatically
part of the subclass.
Object of the subclass
Method from the superclass
28. Inheritance
▪ We can also create objects of a subclass and assign it to
the superclass.
– An object declared to be of superclass A can refer to an instance
of subclass B or C.
– An object declared to be of class Student can reference to an
instance of UGStudent or PGStudent
Student a = new PGStudent();
PGStudent a = new PGStudent();
Object from the subclass
Assigned to superclass
29. Interfaces
▪ We have seen how one class extends another class.
▪ A related concept is implementing an interface.
▪ interface : like a class
– It has methods, attributes etc…
▪ …but…
– We don’t give any details i.e. no bodies to any method.
▪ So an interface just gives what a class would look
like to the outside, without giving any details.
30. Interfaces
▪ If we have an interface we can implement it.
▪ We say that a class implements an interface if it
gives the method bodies to all the methods in the
interface.
▪ We must write all the methods in an interface.
▪ We can write more methods that are not in the
interface.
31. Interfaces
▪ So if we have:
interface MyInterface {
void MethodA();
void MethodB();
}
public class MyClass implements MyInterface{
public void MethodA() {
System.out.println(“My Method A");
}
public void MethodB() {
System.out.println(“My Method B");
}
}
• We can implement this as follows:
32. Interfaces
▪ Interfaces are helpful because I know that if MyClass
implements MyInterface, then I know that MyClass
must have:
– a method void MethodA()
– a method void MethodB()
▪ So if I create an object MyObject from a class that
implements MyInterface, I know I will be able to say
MyObject.MethodA()
33. Inheritance and Interfaces
▪ Inheritance gives us a way of creating classes from
other classes
▪ Interfaces give us a way of defining what methods a
class should have without defining the method.
35. Back to GUIs
▪ Now lets bring this back to GUIs…
▪ We have seen how the things that make a window are
objects of various GUI classes (like JFrame, JOptionPane,
JButton …)
▪ So far, we have created an object from these classes
and then changed their attributes.
▪ Instead we can inherit from these classes are create
out own, more specialized classes
- in particular JFrame
36. GUIs
import javax.swing.*;
public class MyFrame extends JFrame{
MyFrame(){
setTitle("My Frame.");
setSize(200,200);
setLocation(300,300);
setDefaultCloseOperation(EXIT_ON_CLOSE);
}
}
▪ Notice how this class calls the methods
setTitle() and setSize() – how can it do this?
JFrame
MyFrame
37. GUIs
▪ Now we can create objects of the
MyFrame class that we have just written:
public class L7 {
public static void main(String[] args) {
MyFrame mf = new MyFrame();
mf.setVisible(true);
}
}
We didn’t write this method – it was
inherited from the JFrame class, so it
is past of our MyFrame, because
MyFrame is a subclass of JFrame.
38. GUIs
public class MyBlueFrame extends JFrame{
public static void main(String[] args) {
MyBlueFrame mbf = new MyBlueFrame();
}
}
• Go one step further…
• We can even write this as the main class and have a main
method as one of its methods.
– Will have a main method
– This class should extend JFrame class
40. GUIs
• Let’s overload this constructor with a version that takes in
the size of the frame.
MyBlueFrame(String title, int x, int y){
setTitle(title);
setSize(x,y);
setLocation(300,300);
setDefaultCloseOperation(EXIT_ON_CLOSE);
}
• Now let’s say we want to set limits on the size of
the frame – these should be accessible by the user
• Let’s use class constants to do this!
41. GUIs
public static int MAX_X = 250, MAX_Y = 250;
public static void main(String[] args) {...}
MyBlueFrame(String title, int x, int y){
setTitle(title);
if (x > MAX_X)
x = MAX_X;
if (y > MAX_Y)
y = MAX_Y;
setSize(x, y);
setLocation(300,300);
setDefaultCloseOperation(EXIT_ON_CLOSE);
}
42. GUIs
public static int MAX_X = 250, MAX_Y = 250;
public static void main(String[] args) {...}
MyBlueFrame(String title, int x, int y){
setTitle(title);
setSize(x > MAX_X ? MAX_X : x, y > MAX_Y ? MAX_Y : y);
setLocation(300,300);
setDefaultCloseOperation(EXIT_ON_CLOSE);
}
• These are class constants
• We can use MAX_X instead of MyBlueFrame.MAX_X
because we are inside the MyBlueFrame class.
43. GUIs
void SetBackgroundToBlue() {
Container cp = getContentPane();
cp.setBackground(Color.BLUE);
}
• Let’s add a function that changes the background to blue…
• Why getContentPane() and not frame.getContentPane()?
• Because getContentPane() is an object method that is a
member of JFrame objects – objects created from our class
are JFrame objects!
44. GUIs
public class MyBlueFrame extends JFrame{
public static void main(String[] args) {
MyBlueFrame mbf = new MyBlueFrame("My blue frame");
mbf.SetBackgroundToBlue();
mbf.setVisible(true);
}
}
• In the main method, should I use mbf.SetBackgroundToBlue()
or SetBackgroundToBlue()?
• Is this an object method or a class method?
• Does this method belong to the class or does it only
correspond to a particular object?
• Object method!