JAVA PROGRAMMING – Packages - Stream based I/O
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This document provides an overview of packages, interfaces, and stream-based I/O in Java. It defines a package, discusses access protection and importing packages. Interfaces are introduced as a way to achieve multiple inheritance in Java. Key characteristics of interfaces like not allowing implementation and only containing abstract methods are described. The relationship between interfaces and abstract classes is compared. Common interfaces like Comparable are explained. Finally, stream-based I/O concepts like character streams, reading/writing files and serialization are listed as topics to be covered. Universities questions on these topics are also provided.
JAVA PROGRAMMING – Packages - Stream based I/O
- 1. JAVA PROGRAMMING – Packages - Stream based I/O Dr R Jegadeesan Prof-CSE Jyothishmathi Institute of Technology and Science, Karimnagar
- 2. SYLLABUS Packages- Defining a Package, CLASSPATH, Access protection, importing packages. Interfaces- defining an interface, implementing interfaces, Nested interfaces, applying interfaces, variables in interfaces and extending interfaces. Stream based I/O (java.io) – The Stream classes-Byte streams and Character streams, Reading console Input and Writing Console Output, File class, Reading and writing Files, Random access file operations, The Console class, Serialization, Enumerations, auto boxing, generics.
- 3. UNIT 2 : PACKAGES, INTERFACES, STREAM BASED I/O Topic Name : Introduction to Packages, Interfaces, Stream based I/O Topic : Introduction to Packages, Interfaces, Stream Based I/O Aim & Objective : To make the student understand the concepts of creation of packages, interfaces and stream classes Application With Example :Java programs to create and access the packages and implementing interfaces. Java program to read and write data from and to streams. Limitations If Any : Reference Links : • http://javabeginnerstutorial.com/core-java/ • Java The complete reference, 9th edition, Herbert Schildt, McGraw Hill Education (India) Pvt. Ltd. • https://www.tutorialride.com/core-java/packages-interfaces-in-java.htm • Video Link details • https://www.youtube.com/watch?v=iIwyrdc3Zvw
- 4. Universities & Important Questions : • Define a package. What is the necessity of packages? • What are the packages provided by Java API? • Discuss about packages of java language • What is a package? How do we design a package? • What is package? Explain the procedure to create a package with the help of example • How do you create a package? Explain about access protection in packages. • What is the major difference between an interface and class? • Compare and contrast between class and an interface. • Define abstract class and interface and what the difference between them and explain with Suitable examples • How to design and implement an interface? Explain with example. • What is multiple inheritance? Explain how it can be implemented in Java with the help of an example • Explain how interfaces can be implemented. • Write an interface called Shape with necessary methods. Derived classes circle, rectangle, triangle, cone, sphere and cube with appropriate constructors and methods for area, volume also setting and displaying. • Java does not support multiple inheritance. Then how is the problem solved explain with suitable example.
- 5. ▪ Packages ▪ Interfaces ▪ Stream based I/O ▪ Serialization ▪ Enumeration ▪ Generics UNIT – II CONTENTS
- 6. Interfaces • In Java, only single inheritance is permitted. However, Java provides a construct called an interface which can be implemented by a class. • Interfaces are similar to abstract classes (we will compare the two soon). • A class can implement any number of interfaces. In effect using interfaces gives us the benefit of multiple inheritance without many of it’s problems. • Interfaces are compiled into bytecode just like classes. • Interfaces cannot be instantiated. • Can use interface as a data type for variables. • Can also use an interface as the result of a cast operation. • Interfaces can contain only abstract methods and constants.
- 7. Interfaces (cont) • An interface is created with the following syntax: modifier interface interfaceID { //constants/method signatures }
- 8. Syntax public class Circle extends GeometricObject implements Comparable { /* define class here make sure to implement all the abstract methods contained in the interface(s)*/ }
- 9. Interfaces (cont) • An interface can extend other interfaces with the following syntax: modifier interface interfaceID extends comma-delimited-list-of-interfaces { //constants/method signatures } • Obviously, any class which implements a “sub-interface” will have to implement each of the methods contained in it’s “super-interfaces”
- 10. Interface Abstract class Fields Only constants Constants and variable data Methods No implementation allowed (no abstract modifier necessary) Abstract or concrete Interface vs. abstract class
- 11. Interface vs. abstract class (cont) Interface Abstract class Inheritance A subclass can implement many interfaces A subclass can inherit only one class Can extend numerous interfaces Can implement numerous interfaces Cannot extend a class Extends one class
- 12. Interface vs. abstract class (cont) Interface Abstract class Root none Object (of all classes) names Adjective or Nouns Nouns
- 13. Comparable interface • This interface imposes a total ordering on the objects of each class that implements it. This ordering is referred to as the class's natural ordering, and the class's compareTo method is referred to as its natural comparison method. int compareTo (Object o) Compares this object with the specified object for order. Returns a negative integer, zero, or a positive integer as this object is less than, equal to, or greater than the specified object.
- 14. Thank you