The topics covers in this presentation is overloading methods,Construcotr
1 Objects as parameter to methods
2 objects as parameter to construcotr
3 Returning objects
4 String Class
5 String Buffer Class
6 Command line arguments
7 Access Controle
8 Static keyword usage
9 Final keyword usage
The document discusses various types of arrays in Java, including one-dimensional arrays, multi-dimensional arrays, and jagged arrays. It explains how to declare, initialize, access, and pass array elements. Key points include that arrays are dynamically allocated objects that can store primitive values or objects, arrays inherit from Object and implement Serializable and Cloneable, and the class name of an array returns [ followed by the data type (e.g. [I for int array). The document also demonstrates various array examples using for loops and exceptions like ArrayIndexOutOfBoundsException.
Encapsulation provides benefits such as reducing complexity, ensuring structural changes remain local, and allowing for validation and data binding. It works by hiding implementation details and wrapping code and data together. Objects use private fields and public getters/setters for access. Access modifiers like private, protected, and public control visibility. Validation occurs in setters through exceptions. Mutable objects can be modified after creation while immutable objects cannot. The final keyword prevents inheritance, method overriding, or variable reassignment.
The document discusses Object Calisthenics, which are 9 rules for better software design invented by Jeff Bay. The rules are aimed at improving object-oriented programming and include steps like only using one level of indentation per method, not using abbreviations, keeping all entities small, and avoiding getters/setters. The document provides an example of refactoring some code based on these rules and concludes that Object Calisthenics principles can be applied to many programming languages to improve code quality and design.
Inheritance is a mechanism in Java that allows one class to acquire the properties (fields and methods) of another class. The class that inherits is called the subclass, and the class being inherited from is called the superclass. This allows code reuse and establishes an is-a relationship between classes. There are three main types of inheritance in Java: single, multilevel, and hierarchical. Method overriding and dynamic method dispatch allow subclasses to provide their own implementation of methods defined in the superclass.
The document discusses collections in C# programming. It shows examples of using List and Dictionary collections to store and retrieve data. A List is used to store integer values and later iterate through them. A Dictionary is used to store Customer objects mapped by ID. The document also demonstrates converting between collection types using ConvertAll and a custom converter.
This document discusses constructors and destructors in C# classes. It explains that objects must be instantiated using the "new" keyword before their methods can be called. Static methods can be called directly on the class without creating an object instance. Instance variables are unique to each object, while static variables are shared among all objects of a class. The document uses several code examples to demonstrate how to properly create object instances and call both static and instance methods and variables.
Inheritance allows classes to extend and inherit properties from base classes. This creates class hierarchies where subclasses inherit and can override methods from superclasses. Inheritance promotes code reuse through extension when subclasses share the same role as the base class. Composition and delegation are alternative approaches to code reuse that may be preferable in some cases over inheritance.
The document discusses Java operators, arrays, packages, and Javadoc comments. It includes code examples demonstrating the use of arithmetic, unary, and relational operators. It also shows how to declare and initialize single and multi-dimensional arrays. Examples of user-defined packages and importing packages are provided. Finally, it briefly explains what Javadoc comments are and their purpose.
The document discusses various types of arrays in Java, including one-dimensional arrays, multi-dimensional arrays, and jagged arrays. It explains how to declare, initialize, access, and pass array elements. Key points include that arrays are dynamically allocated objects that can store primitive values or objects, arrays inherit from Object and implement Serializable and Cloneable, and the class name of an array returns [ followed by the data type (e.g. [I for int array). The document also demonstrates various array examples using for loops and exceptions like ArrayIndexOutOfBoundsException.
Encapsulation provides benefits such as reducing complexity, ensuring structural changes remain local, and allowing for validation and data binding. It works by hiding implementation details and wrapping code and data together. Objects use private fields and public getters/setters for access. Access modifiers like private, protected, and public control visibility. Validation occurs in setters through exceptions. Mutable objects can be modified after creation while immutable objects cannot. The final keyword prevents inheritance, method overriding, or variable reassignment.
The document discusses Object Calisthenics, which are 9 rules for better software design invented by Jeff Bay. The rules are aimed at improving object-oriented programming and include steps like only using one level of indentation per method, not using abbreviations, keeping all entities small, and avoiding getters/setters. The document provides an example of refactoring some code based on these rules and concludes that Object Calisthenics principles can be applied to many programming languages to improve code quality and design.
Inheritance is a mechanism in Java that allows one class to acquire the properties (fields and methods) of another class. The class that inherits is called the subclass, and the class being inherited from is called the superclass. This allows code reuse and establishes an is-a relationship between classes. There are three main types of inheritance in Java: single, multilevel, and hierarchical. Method overriding and dynamic method dispatch allow subclasses to provide their own implementation of methods defined in the superclass.
The document discusses collections in C# programming. It shows examples of using List and Dictionary collections to store and retrieve data. A List is used to store integer values and later iterate through them. A Dictionary is used to store Customer objects mapped by ID. The document also demonstrates converting between collection types using ConvertAll and a custom converter.
This document discusses constructors and destructors in C# classes. It explains that objects must be instantiated using the "new" keyword before their methods can be called. Static methods can be called directly on the class without creating an object instance. Instance variables are unique to each object, while static variables are shared among all objects of a class. The document uses several code examples to demonstrate how to properly create object instances and call both static and instance methods and variables.
Inheritance allows classes to extend and inherit properties from base classes. This creates class hierarchies where subclasses inherit and can override methods from superclasses. Inheritance promotes code reuse through extension when subclasses share the same role as the base class. Composition and delegation are alternative approaches to code reuse that may be preferable in some cases over inheritance.
The document discusses Java operators, arrays, packages, and Javadoc comments. It includes code examples demonstrating the use of arithmetic, unary, and relational operators. It also shows how to declare and initialize single and multi-dimensional arrays. Examples of user-defined packages and importing packages are provided. Finally, it briefly explains what Javadoc comments are and their purpose.
To learn about the basic concepts of Object Oriented Programming and Inheritance plus different Inheritance Models and interview questions will be covered.
- An interface in Java is a blueprint of a class that defines static constants and abstract methods. Interfaces are used to achieve abstraction and multiple inheritance in Java. A class implements an interface by providing method bodies for the abstract methods defined in the interface. Interfaces allow for loose coupling between classes.
- The main reasons to use interfaces are for abstraction, to support multiple inheritance functionality, and to achieve loose coupling between classes. An interface is declared using the interface keyword and contains only method signatures, not method bodies. A class implementing an interface must implement all of its methods.
- Interfaces can extend other interfaces, requiring implementing classes to provide implementations for all methods in the inherited interfaces as well. Object cloning uses the clone()
This document provides an introduction to creating and using classes in C#. Key points covered include defining classes with fields, methods, and constructors; using accessibility modifiers like public and private; calling methods and using the this keyword; creating static methods; and using listboxes, comboboxes, and events for selection changes. Examples are provided for defining classes, constructors, static and instance methods, and populating and accessing selection properties of list and combo boxes.
The document provides examples of various Java programming concepts like displaying messages, using control structures like if-else, for loops, methods, constructors, access specifiers, static variables and more. It shows how to write simple Java programs to print messages, integers, use conditional and looping statements. It also explains concepts like default and parameterized constructors, static and non-static methods, different access specifiers and their usage. The examples help learn how different Java features can be used to develop programs with classes, objects and methods.
The document discusses inheritance in Java. It defines key terminology like superclass, subclass, reusability and the extends keyword. It provides examples of single inheritance with an Employee and Programmer class, and multilevel inheritance with an Animal, Dog and BabyDog class. It also covers method overriding, where a subclass provides its own implementation of a method in the superclass. Dynamic method dispatch is explained, where the version of an overridden method that is executed depends on the object type, not the reference variable type. The document concludes with an overview of method overloading.
Java OOP Programming language (Part 3) - Class and ObjectOUM SAOKOSAL
Java OOP Programming language (Part 3) - Class and Object
Oum Saokosal
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Class object method constructors in javaRaja Sekhar
Presented By :
N.V.Raja Sekhar Reddy
www.technolamp.co.in
www.programming9.com
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This document provides an introduction and overview of inheritance in C#, including:
- Inheritance allows classes to extend existing classes, inheriting members and behavior
- Derived classes can call base class constructors via the base keyword
- The protected keyword controls accessibility for inherited members
- Virtual and override enable dynamic binding and polymorphism by allowing derived classes to override base class methods
- Abstract classes define common interfaces for derived classes to implement
Here we are going to learn why is a good practice to use interfaces and how they are different from abstraction classes. Further more we are going to see how which one of them to use.
This document discusses Java packages and access control. It defines packages as namespaces that group related classes, and describes how to declare packages and import other packages. It then covers the four access modifiers in Java (public, protected, no modifier, private) and their effects on class, package, subclass and other package access. Code examples are provided to demonstrate how to define packages and use different access modifiers to control visibility and accessibility of classes, variables and methods in Java.
Defining Simple Classes
Using Own Classes and Objects
Access Modifiers
Constructors and Initializers
Defining Fields
Defining Properties, Getters and Setters
Defining Methods
Exercises: Defining and Using Own Classes
Java is an object-oriented programming language developed by James Gosling at Sun Microsystems in 1995. It allows software to run on any device that supports Java Virtual Machine (JVM), making it platform independent. The core Java technologies include Applets, Servlets, JSP, Swing, EJB, JDBC, Struts, Hibernate, and Spring. Java supports concepts like inheritance, polymorphism, abstraction through classes and interfaces. It also allows overriding methods for inheritance and implements interfaces for multiple inheritance.
The document introduces C# as the first component-oriented language in the C/C++ family. It discusses key features of C# including everything being an object, robust and durable software through garbage collection and exceptions, and preservation of investment from C++. It provides examples of basic C# concepts like classes, structs, interfaces, enums, delegates, properties and events.
The document introduces C# and discusses its key features. It describes C# as the first component-oriented language in the C/C++ family, where everything is an object and it enables robust and durable software through features like garbage collection and exceptions. It also discusses how C# preserves investments in existing software and languages through interoperability. The document provides overviews of major C# concepts like its type system, classes, interfaces, attributes and statements.
In this chapter we will understand how to define custom classes and their elements. We will learn to declare fields, constructors and properties for the classes. We will revise what a method is and we will broaden our knowledge about access modifiers and methods.
This chapter discusses decision making, object-oriented fundamentals, inner classes, and exception handling in Java. It describes the use of if and switch statements for decision making. It also covers access specifiers, encapsulation, inheritance, polymorphism, abstract classes, interfaces, inner classes, and exceptions.
C# is a component-oriented language that introduces object-oriented improvements to the C/C++ family of languages. Key features include garbage collection, exceptions, type safety, and preservation of C++ investments like namespaces and enums. Everything in C# is an object, unifying value and reference types without performance penalties. The language supports robust features like properties, events, generics and attributes to enable component-based development.
This document discusses Java methods. Some key points covered include:
- Methods allow grouping of code to perform operations and are called by name. They can return values.
- Advantages of methods include being time savers, allowing code repetition without retyping, and enabling modular programming.
- The syntax for defining a method includes access modifiers, return type, name, and parameters.
- Methods can be invoked from another method, as shown in an example finding the minimum of two numbers.
This document discusses constructor overloading in C++. It explains that constructor overloading allows a class to have multiple constructors as long as their signatures are different. This allows both initialized and uninitialized objects to be created. It provides examples of initialized objects, which call the constructor and initialize member variables, versus uninitialized objects, which do not initialize member variables. The document also discusses how to explicitly and implicitly call constructors when initializing objects.
Constructors, Destructors, call in parameterized Constructor, Multiple constructor in a class, Explicit/implicit call, Copy constructor, Dynamic Constructors and call in parameterized Constructor
The document discusses constructors and destructors in C++. It defines constructors as special member functions that are used to construct an object's memory and provide initialization. Destructors are special member functions used to destroy an object's memory. The document provides details on the syntax, usage, and types of constructors and destructors. It includes examples to illustrate default constructors, parameterized constructors, copy constructors, and the use of constructors and destructors.
To learn about the basic concepts of Object Oriented Programming and Inheritance plus different Inheritance Models and interview questions will be covered.
- An interface in Java is a blueprint of a class that defines static constants and abstract methods. Interfaces are used to achieve abstraction and multiple inheritance in Java. A class implements an interface by providing method bodies for the abstract methods defined in the interface. Interfaces allow for loose coupling between classes.
- The main reasons to use interfaces are for abstraction, to support multiple inheritance functionality, and to achieve loose coupling between classes. An interface is declared using the interface keyword and contains only method signatures, not method bodies. A class implementing an interface must implement all of its methods.
- Interfaces can extend other interfaces, requiring implementing classes to provide implementations for all methods in the inherited interfaces as well. Object cloning uses the clone()
This document provides an introduction to creating and using classes in C#. Key points covered include defining classes with fields, methods, and constructors; using accessibility modifiers like public and private; calling methods and using the this keyword; creating static methods; and using listboxes, comboboxes, and events for selection changes. Examples are provided for defining classes, constructors, static and instance methods, and populating and accessing selection properties of list and combo boxes.
The document provides examples of various Java programming concepts like displaying messages, using control structures like if-else, for loops, methods, constructors, access specifiers, static variables and more. It shows how to write simple Java programs to print messages, integers, use conditional and looping statements. It also explains concepts like default and parameterized constructors, static and non-static methods, different access specifiers and their usage. The examples help learn how different Java features can be used to develop programs with classes, objects and methods.
The document discusses inheritance in Java. It defines key terminology like superclass, subclass, reusability and the extends keyword. It provides examples of single inheritance with an Employee and Programmer class, and multilevel inheritance with an Animal, Dog and BabyDog class. It also covers method overriding, where a subclass provides its own implementation of a method in the superclass. Dynamic method dispatch is explained, where the version of an overridden method that is executed depends on the object type, not the reference variable type. The document concludes with an overview of method overloading.
Java OOP Programming language (Part 3) - Class and ObjectOUM SAOKOSAL
Java OOP Programming language (Part 3) - Class and Object
Oum Saokosal
Where to me find me more:
YouTube: https://www.youtube.com/user/oumsaokosal
FB Page: https://facebook.com/kosalgeek
PPT: https://www.slideshare.net/oumsaokosal
Twitter: https://twitter.com/okosal
Web: http://kosalgeek.com
Class object method constructors in javaRaja Sekhar
Presented By :
N.V.Raja Sekhar Reddy
www.technolamp.co.in
www.programming9.com
Want more interesting...
Watch and Like us @ https://www.facebook.com/Technolamp.co.in
subscribe videos @ http://www.youtube.com/user/nvrajasekhar
This document provides an introduction and overview of inheritance in C#, including:
- Inheritance allows classes to extend existing classes, inheriting members and behavior
- Derived classes can call base class constructors via the base keyword
- The protected keyword controls accessibility for inherited members
- Virtual and override enable dynamic binding and polymorphism by allowing derived classes to override base class methods
- Abstract classes define common interfaces for derived classes to implement
Here we are going to learn why is a good practice to use interfaces and how they are different from abstraction classes. Further more we are going to see how which one of them to use.
This document discusses Java packages and access control. It defines packages as namespaces that group related classes, and describes how to declare packages and import other packages. It then covers the four access modifiers in Java (public, protected, no modifier, private) and their effects on class, package, subclass and other package access. Code examples are provided to demonstrate how to define packages and use different access modifiers to control visibility and accessibility of classes, variables and methods in Java.
Defining Simple Classes
Using Own Classes and Objects
Access Modifiers
Constructors and Initializers
Defining Fields
Defining Properties, Getters and Setters
Defining Methods
Exercises: Defining and Using Own Classes
Java is an object-oriented programming language developed by James Gosling at Sun Microsystems in 1995. It allows software to run on any device that supports Java Virtual Machine (JVM), making it platform independent. The core Java technologies include Applets, Servlets, JSP, Swing, EJB, JDBC, Struts, Hibernate, and Spring. Java supports concepts like inheritance, polymorphism, abstraction through classes and interfaces. It also allows overriding methods for inheritance and implements interfaces for multiple inheritance.
The document introduces C# as the first component-oriented language in the C/C++ family. It discusses key features of C# including everything being an object, robust and durable software through garbage collection and exceptions, and preservation of investment from C++. It provides examples of basic C# concepts like classes, structs, interfaces, enums, delegates, properties and events.
The document introduces C# and discusses its key features. It describes C# as the first component-oriented language in the C/C++ family, where everything is an object and it enables robust and durable software through features like garbage collection and exceptions. It also discusses how C# preserves investments in existing software and languages through interoperability. The document provides overviews of major C# concepts like its type system, classes, interfaces, attributes and statements.
In this chapter we will understand how to define custom classes and their elements. We will learn to declare fields, constructors and properties for the classes. We will revise what a method is and we will broaden our knowledge about access modifiers and methods.
This chapter discusses decision making, object-oriented fundamentals, inner classes, and exception handling in Java. It describes the use of if and switch statements for decision making. It also covers access specifiers, encapsulation, inheritance, polymorphism, abstract classes, interfaces, inner classes, and exceptions.
C# is a component-oriented language that introduces object-oriented improvements to the C/C++ family of languages. Key features include garbage collection, exceptions, type safety, and preservation of C++ investments like namespaces and enums. Everything in C# is an object, unifying value and reference types without performance penalties. The language supports robust features like properties, events, generics and attributes to enable component-based development.
This document discusses Java methods. Some key points covered include:
- Methods allow grouping of code to perform operations and are called by name. They can return values.
- Advantages of methods include being time savers, allowing code repetition without retyping, and enabling modular programming.
- The syntax for defining a method includes access modifiers, return type, name, and parameters.
- Methods can be invoked from another method, as shown in an example finding the minimum of two numbers.
This document discusses constructor overloading in C++. It explains that constructor overloading allows a class to have multiple constructors as long as their signatures are different. This allows both initialized and uninitialized objects to be created. It provides examples of initialized objects, which call the constructor and initialize member variables, versus uninitialized objects, which do not initialize member variables. The document also discusses how to explicitly and implicitly call constructors when initializing objects.
Constructors, Destructors, call in parameterized Constructor, Multiple constructor in a class, Explicit/implicit call, Copy constructor, Dynamic Constructors and call in parameterized Constructor
The document discusses constructors and destructors in C++. It defines constructors as special member functions that are used to construct an object's memory and provide initialization. Destructors are special member functions used to destroy an object's memory. The document provides details on the syntax, usage, and types of constructors and destructors. It includes examples to illustrate default constructors, parameterized constructors, copy constructors, and the use of constructors and destructors.
Constructors and functions can be overloaded by having the same name but different parameters, allowing multiple implementations. Function overriding occurs when subclasses define functions of the same name and parameters as the parent class. Abstract classes contain abstract methods that are undefined, preventing object creation, and must be implemented in subclasses.
constructor and destructor-object oriented programmingAshita Agrawal
Constructors are special member functions that initialize objects of a class. There are different types of constructors including default, parameterized, and copy constructors. Destructors are used to destroy objects and their name is the same as the class name but preceded by a tilde. Constructors and destructors are important aspects of object oriented programming.
View study notes of Function overloading .you can also visit Tutorialfocus.net to get complete description step wise of the concerned topic.Other topics and notes of C++ are also explained.
This document discusses constructors and destructors in C++. It explains that constructors are special functions called when an object is created that have the same name as the class, cannot return a value, and are used to initialize objects. Destructors are also special functions with the same name as the class but with a ~ sign that cannot return a value and are called when an object is destroyed to cleanup resources. The document aims to help readers understand when and how constructors and destructors are used.
This document discusses constructors and destructors in C++. It defines a constructor as a special member function with the same name as the class that is used to initialize objects. Constructors are called automatically when objects are created and allow objects to be initialized before use. Constructors cannot be inherited or static and default and copy constructors are generated by the compiler. The document also discusses declaration, default arguments, copy constructors, and the order of constructor invocation.
Constructor is a special method in Java that is used to initialize objects. It has the same name as the class and is invoked automatically when an object is created. Constructors can be used to set default values for objects. A class can have multiple constructors as long as they have different parameters. Constructors are used to provide different initial values to objects and cannot return values.
Operator overloading allows operators like +, -, *, etc. to be used with user-defined types by defining specific method implementations. It enables operations on user-defined classes to behave similarly to built-in types. The document provides examples of overloading unary and binary operators in C# classes to change the sign of a number and add two calculator objects respectively. It also discusses the different operators that can and cannot be overloaded and how to define the operator overloading methods with the correct return types and parameters.
object oriented programming using java, second sem BCA,UoMambikavenkatesh2
Constructors are special methods that initialize objects when they are created. They have the same name as the class and do not specify a return type. There are three types of constructors: no-arg, parameterized, and default. Overloaded constructors have the same name but different parameters. The garbage collector deletes unused objects to free up memory. Finalizer methods are called before an object is garbage collected and allow for cleanup.
The document contains 10 Java programs demonstrating various Java concepts:
1. Constructor overloading and method overloading using a Box class.
2. Inner classes and access protections using an Outer and Inner class.
3. Inheritance using classes A and B, with B extending A.
4. Exception handling using nested try-catch blocks.
5. Linked list operations using a LinkedList class.
6. File input/output streams using FileInputStream and FileOutputStream.
7. Object serialization writing an object to a file.
8. Client-server communication using datagram sockets.
9. Mouse event handling using MouseListener and MouseMotionListener interfaces.
10. Keyboard event handling using the
This document provides an overview of classes in Java. It discusses key concepts like class templates, objects, fields, methods, access modifiers, constructors, static members, and class design best practices. Specifically, it defines a class as a template for objects that encapsulates data and functions, and notes that objects are instances of classes. It also explains how to declare fields and methods, the different access levels for class members, and how to define constructors including overloaded and parameterized constructors.
Object Oriented Solved Practice Programs C++ ExamsMuhammadTalha436
The question asks to create classes to represent publications, books, and tapes. The Publication class has title and price attributes. The Book class inherits from Publication and adds a noOfPages attribute. The Tape class inherits from Publication and adds a playingTime attribute.
The document defines classes and methods in Java.
It discusses:
1) The syntax for defining a class with modifiers, data declarations, and method definitions.
2) How a class can contain data declarations and method declarations to store information and perform behaviors.
3) The structure of a method including the header, parameters, and body.
4) How to define constructors, static methods, and overload methods in a class.
Framhald af umfjöllun um hlutbundna forritun og hönnun. Nú förum við yfir Generic Programming sem sem leið til að búa til sveigjanlega og endurnýtanlegar einingar. Skoðum líka reflection. Þá verður farið fyrir hvernig má hann laustengdar einingar og notum við frægan andarleik sem dæmi.
Þá mun Code Horror Dude kíkja í heimsókn
The document provides code examples for several Java programming concepts:
1. A program that takes command line arguments, calculates the sum and average of the numbers passed, and displays the results.
2. A Student class with member functions to read and display student details like name and age.
3. A Square class with data members for length, area, and perimeter, and member functions to read, compute values, and display details.
The document contains 10 additional examples covering topics like inheritance, packages, exceptions, threads, and GUI programming.
The document describes object-oriented programming concepts related to inheritance. It shows how a derived class called ExtTime inherits from a base Time class, allowing ExtTime to inherit Time's properties and methods while also adding its own private data member and overriding the Write() method. ExtTime uses inheritance to extend the functionality of Time for working with time zones.
This document summarizes key concepts in object-oriented programming including:
1) Primitive types like int, long, float, double, char arrays, and boolean that are similar to C primitives.
2) Boxed types that wrap primitive types in objects like Integer and Long.
3) Type conversion between primitives and objects.
4) Strings are objects that can be concatenated or modified.
5) Methods can be static or require an object instance. Constructors are special methods that initialize objects.
6) Access modifiers like public, private, and protected control the scope of classes, methods, and variables.
This document discusses several Java programming concepts including nested classes, object parameters, recursion, and command line arguments. Nested classes allow a class to be declared within another class and access private members of the outer class. Objects can be passed as parameters to methods, allowing the method to modify the object's fields. Recursion is when a method calls itself, such as a recursive method to calculate factorials. Command line arguments allow passing input to a program when running it from the command line.
This document provides an overview of key object-oriented programming concepts including classes and objects, inheritance, encapsulation, polymorphism, interfaces, abstract classes, and design patterns. It discusses class construction and object instantiation. Inheritance is described as both exposing implementation details and potentially breaking encapsulation. Composition is presented as an alternative to inheritance. The document also covers method overriding, overloading, and duck typing as forms of polymorphism. Finally, it briefly introduces common design principles like SOLID and patterns like delegation.
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.
The document discusses inheritance in C++. It shows how a derived class can inherit properties and behaviors from a base class, while also adding its own properties and overriding or specializing inherited behaviors. Examples include a Polygon base class that is derived into Rectangle and Triangle classes, and a Time base class derived into an ExtTime class that adds time zone tracking. Inheritance allows defining hierarchies of related classes to reduce duplication and extend functionality.
The document discusses inheritance in C++. It shows how a derived class can inherit properties and behaviors from a base class, while also adding its own private data members and defining its own public member functions, including overriding virtual functions from the base class. The key aspects covered are:
- Defining derived classes that inherit publicly or privately from a base class
- Access control of inherited members depending on inheritance type
- Calling base class constructors from derived class constructors
- Derived classes augmenting the base class with additional data and functions
- Overriding functions to specialize behavior while reusing the base class interface
This chapter discusses user-defined classes and abstract data types (ADTs) in Java. It covers defining classes with private, protected, public, and static members. Constructors and finalizers are examined. The toString method is explored. Abstract data types are introduced as data types that specify logical properties without implementation details. An example candy machine problem is presented to demonstrate defining classes for a non-GUI and GUI application to model a candy machine with items for sale, a cash register, dispenser, and other components.
This document provides an overview of various Java programming concepts including methods, command line arguments, constructors, this keyword, super keyword, static keyword, final keyword, and finally block. It discusses how to define methods with and without return values, pass parameters, and overload methods. It explains how to pass command line arguments to the main method. It describes the different types of constructors and how to use this and super keywords. It discusses how to declare static variables, methods, blocks, and nested classes. It also explains how to use the final keyword to create constant variables.
The Toolbar is a view introduced in Android Lollipop that is easier to customize and position than the ActionBar. It can be used on lower Android versions by including the AppCompat support library. To use the Toolbar as an ActionBar, disable the theme-provided ActionBar, add the Toolbar to the activity layout, and include dependencies for AppCompat and Design support libraries.
The singleton pattern ensures that only one instance of a class is created. It involves a class that instantiates itself and makes sure no other instances are created, providing a global point of access to the sole instance. Examples of where the singleton pattern is commonly used include logger classes, configuration classes, accessing shared resources, and singleton factories.
Object-relational mapping products like ORMLite integrate object programming with relational databases. ORMLite avoids complexity and overhead by providing lightweight functionality to persist Java objects to SQL databases using annotations and abstract DAO classes. It allows flexible querying and supports basic transactions while automatically generating SQL for database creation and dropping.
This document shows how to add an action listener to a button in Java. It imports necessary classes like JButton and ActionListener. It creates a JFrame with a button that displays a message dialog when clicked. The button is given an action listener that calls showMessageDialog when the button's actionPerformed method is triggered. The button is added to a panel and frame for display.
The Java Collections Framework provides useful classes for storing and processing data efficiently. It includes the List interface which supports ordered elements that may be duplicated. The ArrayList and LinkedList classes implement the List interface but differ in performance - ArrayList uses an array for fast random access while LinkedList uses nodes for fast insertion/removal. The Set interface does not allow duplicates. Implementations like HashSet, TreeSet and LinkedHashSet vary in ordering and performance. The ArrayDeque class implements a double-ended queue for fast insertion/removal at both ends. Collections methods like sort() and reverse() can organize elements in lists.
This document discusses key concepts in Java including packages, access specifiers, interfaces, multiple inheritance, extending interfaces, and the differences between abstract classes and interfaces. Packages allow grouping of related classes and interfaces. Access specifiers determine visibility of classes, interfaces, and members. Interfaces define behaviors without implementations, and classes implement interfaces. Multiple inheritance is supported through interfaces in Java. Interfaces can extend other interfaces. Abstract classes contain abstract and concrete methods while interfaces contain only abstract methods.
This document shows how to add an action listener to a button in Java. It imports necessary classes like JButton and ActionListener. It creates a JFrame with a button that displays a message dialog when clicked. The button is given an action listener that calls showMessageDialog when the button's actionPerformed method is triggered. The button is added to a panel and frame for display.
Dynamic method dispatch allows the determination of which version of an overridden method to execute at runtime based on the object's type. Abstract classes cannot be instantiated and can contain both abstract and concrete methods. Final methods and classes prevent inheritance and overriding.
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2. There are three types of inheritance in Java: single, multilevel, and hierarchical. Single inheritance involves one subclass extending one superclass, while multilevel involves deriving a subclass from another derived class. Hierarchical inheritance involves one superclass being inherited by multiple subclasses.
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This document discusses various control flow statements in Java including branching statements, looping statements, and jump statements. It provides examples of if, if-else, if-else-if statements, switch statements, for loops, while loops, do-while loops, break, continue, and return statements. Key points include:
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- Jump statements like break and continue control flow within loops, while
Applets are small Java programs that run in web browsers. They have a lifecycle with methods like init(), start(), paint(), stop(), and destroy() that get called at different points. The init() method initializes variables, start() runs when the applet is displayed, paint() redraws the output, stop() runs when the browser closes, and destroy() removes the applet from memory. Sample code shows an applet class that extends Applet and overrides these methods to track calls and draw status messages. The status window can also be used to display messages to users.
A review of the growth of the Israel Genealogy Research Association Database Collection for the last 12 months. Our collection is now passed the 3 million mark and still growing. See which archives have contributed the most. See the different types of records we have, and which years have had records added. You can also see what we have for the future.
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1. Closer look at classes
Overloading Methods
Overloading Constructor
Objects as parameter to methods
Objects as parameter to constructor
Returning Objects
Recursion
String Class
String Buffer Class
Command line arguments
Access Controle
Static Keyword Usage
Final Keyword Usage
2. Overloading methods
• Overloading is ability of one function to perform different tasks.
• it allows creating several methods with the same name which differ from each
other in the type of the input and the output
class Demo_class
{ /* having same method name*/
void demo()
{ System.out.println("hello world"); }
void demo(int a)
{ System.out.println("the value of a::"+a); }
public static void main(String[] y)
{ Demo_class d=new Demo_class();
d.demo();
d.demo(10);
}
}
3. Overloading Constructor
• In addition to overloading normal methods,you can also overload
constructor methods
class Demo_Constructor_overload
{ Demo_Constructor_overload()
{ System.out.println("hello default constructor");
}
Demo_Constructor_overload(String s)
{ System.out.println("hello default constructor 1::"+s);
}
public static void main(String[] a1)
{ Demo_Constructor_overload d=new Demo_Constructor_overload();
Demo_Constructor_overload d1=new Demo_Constructor_overload
("yugandhar");
}
}
4. Uses of method Overloading
• The main advantage of this is cleanliness of
code.
• the use of function overloading is to save the
memory space, consistency and readabiliy.
5. Objects as parameters to methods
class Rectangle
{ int lenght,width;
Rectangle(int lenght,int width)
{ this.lenght=lenght;
this.width=width;
}
void print_values(Rectangle r)
{ System.out.println("the value of member length "+r.lenght+"n the
value of member variable width is::"+this.width);
}
}
public class Demo_object_paramter
{ public static void main(String[] y)
{ Rectangle r=new Rectangle(10,20);
r.print_values(r);
}
}
6. Objects as parameters to Constructor
class Rectangle
{ int lenght,width;
Rectangle(int lenght,int width)
{ this.lenght=lenght;
this.width=width;
}
Rectangle(Rectangle r)
{ System.out.println("the member varialbe lenght::"+r.lenght+"n the
member varialbe height::"+r.width);
}
}
public class Demo_object_paramter
{ public static void main(String[] y)
{ Rectangle r=new Rectangle(30,20);
Rectangle r1=new Rectangle(r);
}
}
7. Returning objects
• A method can return any type of data,including class types that you create
class Rectangle
{ int length,width;
Rectangle demo(int length,int width)
{ this.length=length;
this.width=width;
return(this);
}
}
public class Demo_object_paramter
{ public static void main(String[] y)
{ Rectangle r=new Rectangle();
Rectangle r1=r.demo(30,40);
System.out.println("the value of length is::"+r1.length+"n the value of
width is::"+r1.width);
}
}
8. Recursion
• Recursion is a basic programming technique you can use in Java, in which a
method calls itself to solve some problem.
• A method that uses this technique is recursive.
class Factorial
{ int fact(int n)
{ int result;
if(n==1)
return 1;
result=fact(n-1)*n;
return result;
}
}
public class Recursion_1
{ public static void main(String[] y)
{ Factorial f=new Factorial();
System.out.println("the factorial value is::"+f.fact(5));
}
}
9. String Class
• The first thing to understand about strings is that every string you create is
actually an object of type string . Every string constant is actually a string
Object.
• Eg System.out.println(“hello world”);
• The secound thing to understand about strings is that objects of type
String are immutable once string objects are created ,its content can not
be altered.
public class Private_AccessDemo
{ public static void main(String[] y)
{ String s=new String("yugandhar");
System.out.println("the s String is::"+s);
System.out.println("the String length::"+s.length());
String s1=new String("programmer");
System.out.println("the String concatination "+s+s1);
}
}
10. Declaring String Array
public static void main(String[] y)
{ String[] s=new String[3];//string array with 3
Scanner sc=new Scanner(System.in);//taking input at run time from user
for(int i=0;i<s.length;i++)
s[i]=sc.nextLine();
for(int i=0;i<s.length;i++)
System.out.println(" "+s[i]);
}
11. Some String Methods
public class Private_AccessDemo
{ public static void main(String[] y)
{ String s="yugandhar";
System.out.println("the upper case::"+s.toUpperCase());
System.out.println("the upper case::"+s.toLowerCase());
System.out.println("the replace ::"+s.replace('a','r'));
System.out.println("the charAt ::"+s.charAt(8));
}
}
12. String Buffer Class
• String Buffer creates the string of flexible length that can be modified in
terms content and length. We can insert characters and substrings in the
middle of the string are append another string at the end.
public class Private_AccessDemo
{ public static void main(String[] y)
{ StringBuffer s=new StringBuffer("yugandhar");//StringBuffer constructor
System.out.println("the String Buffer class");
s.setCharAt(6,'x');//methods of String Buffer class
System.out.println(s);
System.out.println("the append string::"+s.append(" programmer"));
s.setLength(40);// methods of String Buffer class
System.out.println("the set length ::"+s.length());
}
}
13. Command line arguments
• A command-line argument is the information that directly follows the
program’s name on the command line when it is excuted .
• All command line arguments are passed as strings
public static void main(String[] y)
{ System.out.println("the commandline arguments");
for(int i=0;i<y.length;i++)
System.out.println("the y["+i+"]::"+y[i]);
}
####output####
D:softwaresjava_programs>java Private_AccessDemo h e l l o w
the commandline arguments
the y[0]::h the y[1]::e the y[2]::l the y[3]::l the y[4]::o
the y[5]::w
14. Access Control
• encapsulation provides another important attribute: access control.
• Java’s access specifiers are public, private, and protected
• Public: A class, method, constructor, interface etc declared public can be
accessed from any other class. Therefore fields, methods, blocks declared
inside a public class can be accessed from any class
• private: Methods, Variables and Constructors that are declared private can
only be accessed within the declared class itself. Private access modifier is
the most restrictive access level. Class and interfaces cannot be private
• protect: Variables, methods and constructors which are declared protected
in a superclass can be accessed only by the subclasses in other package or
any class within the package of the protected members' class. The
protected access modifier cannot be applied to class and interfaces.
• Default: access modifier means we do not explicitly declare an access
modifier for a class, field, method, etc.A variable or method declared
without any access control modifier is available to any other class in the
same package.
15. Public access specifier
package demo_package;
import java.util.*;
public class AccessDemo
{ public void test()
{ System.out.println("Example of public access specifier"); }
protected int x=200;
}
D:softwaresjava_programs>javac -d . AccessDemo.java
import java.util.*;
import demo_package.AccessDemo;
public class Public_AccessDemo
{ public static void main(String[] y)
{ AccessDemo d=new AccessDemo();
d.test();
}
}
####output####
D:softwaresjava_programs>javac Public_AccessDemo.java
D:softwaresjava_programs>java Public_AccessDemo
Example of public access specifier
16. Private Access modifyer
class demo
{ private int x=20;
private void demo()
{ System.out.println("the value of x is::"+x);
}
void demo_1()
{ System.out.println("the demo_1 value of x is::"+x);
}
}
public class Private_AccessDemo
{ public static void main(String[] y)
{ demo d=new demo();
System.out.println("the value of x is"+d.x);
d.demo();
d.demo_1();
}
}
####output####
D:softwaresjava_programs>javac Private_AccessDemo.java
error: x has private access in demo
System.out.println("the value of x is"+d.x);
: error: demo() has private access in demo
d.demo()
making the d.demo_1() above two lines as comment then following out put will get
D:softwaresjava_programs>java Private_AccessDemo
the demo_1 value of x is::20
17. Protected access specifyer
import java.util.*;
import demo_package.AccessDemo;
class demo
{ protected int x=20;
protected void demo()
{ System.out.println("the value of x is::"+x); }
}
public class Private_AccessDemo extends AccessDemo
{ public static void main(String[] y)
{ demo d=new demo(); d.x=30;
System.out.println("the value of x is "+d.x); d.demo();
/*try with this code to know the difference with out extends AccessDemo
AccessDemo a=new AccessDemo();
System.out.println(a.x);
-*/
Private_AccessDemo a=new Private_AccessDemo();
System.out.println(a.x);
}
}
D:softwaresjava_programs>java Private_AccessDemo
the value of x is 30 the value of x is::30 200
18. Static
Variable declaration with Static
• When a variable is declared with the keyword “static”, its called a “class variable”.
• All instances share the same copy of the variable.
• A class variable can be accessed directly with the class, without the need to create a instance.
class static_
{ static String y="i am static variable";
String y1="hello_world";
}
public class Static_Demo
{ public static void main(String[] y)
{ System.out.println("accessing static variable::"+static_.y);
static_ s=new static_();
s.y="hello";
s.y1="H";
//static_.y="done";
System.out.println("accessing static variable::"+static_.y);
/*
* here y shares the same copy
*/
static_ s1=new static_();
System.out.println("accessing static variable::"+s1.y+"n the value of y1::"+s1.y1);
}
}
19. Method declaration with static
• It is a method which belongs to the class and not to the object(instance)
• A static method can access only static data. It can not access non-static
data (instance variables)
• A static method can call only other static methods and can not call a non-
static method from it.
• A static method can be accessed directly by the class name and doesn’t
need any object
• Syntax : <class-name>.<method-name>
• A static method cannot refer to “this” or “super” keywords in anyway
20. class static_
{ int x=10;
static void demo()
{ System.out.println("hellow static method");
// System.out.println("the value of x is"+x);
/*
* static methods can call only other static methods
* and other static variables only
*/
//demo_1();
demo_2();
}
void demo_1()
{ System.out.println("not static method demo_1()"); }
static void demo_2()
{ System.out.println(" static method demo_2()"); }
}//class
public class Static_Demo
{ static void demo_3()
{ System.out.println("the main methods static"); }
public static void main(String[] y)
{ System.out.println("static method");
static_.demo();
demo_3();
}
}
####output####
static method
hellow static method
static method demo_2()
the main methods static
21. Static block
• The static block, is a block of statement inside a Java class that will be executed when
a class is first loaded in to the JVM.
class static_
{ int x=10;
void demo()
{ System.out.println("hellow"); }
static{ System.out.println("secound static block");
}
static{ System.out.println("first static block");
}
}
public class Static_Demo
{ public static void main(String[] y)
{ static_ s=new static_();
s.demo();
}
}
####output####
secound static block
first static block
hellow
22. final keyword
• final is a reserved keyword in Java to restrict the user and it can be applied
to member variables, methods, class and local variables.
class Demo
{ final int INT_VARIABLE=120;
/**final variable value can not be chage */
public static void main(String[] y)
{ Demo d=new Demo();
d.INT_VARIABLE=45;
}
}
####output####
C:UsersYugandharDesktopjsp>javac Demo.java
Demo.java:8: error: cannot assign a value to final variable INT_VARIABLE
d.INT_VARIABLE=45;
23. Final method
• A final method cannot be overridden. Which means even though a sub
class can call the final method of parent class without any issues but it
cannot override it.
class Super
{ final void demo()
{ System.out.println("hello"); }
}
class Sub_ extends Super
{ /*void demo()
{
System.out.println("hello world");
}*/
void demo_1()
{ System.out.println("hello world"); }
}
class Demo
{ public static void main(String[] y)
{ Sub_ s=new Sub_();
s.demo();
}
}
try to remove those comments to understand
####output####
C:UsersYugandharDesktopjsp>javac Demo.java
Demo.java:11: error: demo() in Sub_ cannot override demo() in Super
C:UsersYugandharDesktopjsp>java Demo
hello
24. Final class
• We cannot extend a final class prevent inheritance
final class Super
{ void demo()
{ System.out.println("hello"); }
}
class Sub_ extends s
{ void demo_1()
{ System.out.println("hello world"); }
}
class Demo
{ public static void main(String[] y)
{ Sub_ s=new Sub_(); }
}
####output####
C:UsersYugandharDesktopjsp>javac Demo.java
Demo.java:9: error: cannot inherit from final Super
class Sub_ extends Super
25. Uses of final keyword
• Using final to define constants
• Using final to prevent inheritance
• Using final to prevent overriding
• Using final for method arguments