JAVA NOTES FOR ALL
Consider the following important ideas and considerations when dealing with Java:
Java is an object-oriented programming language, which means it places a strong emphasis on the idea of objects that encapsulate information and behaviour. Encapsulation, inheritance, and polymorphism are important OOP tenets.
Syntax and Organisation: Classes are used as building blocks for objects while writing Java programming. Each class consists of variables (fields) for data storage and functions (methods) for behaviour definition. A main() function is often where Java programmes begin to run.
Primitive and reference types are the two basic categories of data types in Java. Integer, double, and boolean types are examples of primitive types, whereas objects, arrays, and strings are examples of reference types.
Control Flow: Java has statements for controlling the flow of execution based on conditions, including if-else, switch-case, for loops, while loops, and do-while loops.
Exception Handling: Runtime errors and extraordinary circumstances are handled by Java's exception handling framework. Try-catch blocks are used to capture exceptions and gracefully handle them.
Packages and Imports: In Java, packages enable class organisation and prevent naming conflicts. To include classes from other packages in the current class, use the import statement.
Java classes can use the "extends" keyword to take on traits and traits from other classes. Inheritance encourages the idea of a class hierarchy and enables for code reuse.
Interfaces: Interfaces specify the methods that a class is required to implement. They facilitate abstraction and multiple inheritance-like behaviour.
Collections: The Java Collections Framework offers a wide variety of collection classes. Groups of items can be stored and manipulated using these classes, which include ArrayList, LinkedList, HashMap, etc.
Java provides multithreading, which enables programmes to carry out numerous tasks at once. For creating and maintaining threads, utilise the Thread class and the Runnable interface.
Java offers classes and APIs for processes involving input and output. While java.util.Scanner is frequently used to read input from the user, the java.io package provides capability for reading from and writing to files.
Java has a powerful exception handling system that allows it to catch and deal with errors as they occur. To handle probable exceptions, try-catch blocks are used, and finally blocks are used to run cleanup code.
To get you started with Java, these are only a few essential ideas. It is a sizable programming language that has a wide range of features and skills. Examining official Java tutorials and documentation will give you additional in-depth information and examples to improve your comprehension and abilities.
SYLLABUS
INTRODUCTION TO JAVA PROGRAMMING
Objectives:
This subject aims to introduce students to the Java programming language. Upon successful completion of this subject, students should be able to create Java programs that leverage the object-oriented features of the Java language, such as encapsulation, inheritance and polymorphism; use data types, arrays and other data collections; implement error-handling techniques using exception handling, create and event-driven GUI using Swing components.
UNIT-I
OOP Concepts:-Data abstraction, encapsulation, inheritance, Benefits of Inheritance, Polymorphism, classes and objects, Procedural and object oriented programming paradigms.
Java Programming- History of Java, comments, Data types, Variables, Constants, Scope and Lifetime of variables, Operators, Operator Hierarchy, Expressions, Type conversion and casting, Enumerated types, Control flow- block scope, conditional statements, loops, break and continue statements, simple java stand alone programs, arrays, console input and output, formatting output, constructors, methods, parameter passing, static fields and methods, access control, this reference, overloading methods and constructors, recursion, garbage collection, building strings, exploring string class.
UNIT – II
Inheritance – Inheritance hierarchies super and sub classes, Member access rules, super keyword, preventing inheritance: final classes and methods, the Object class and itsmethods.
Polymorphism – dynamic binding, method overriding, abstract classes and methods.
Interfaces- Interfaces Vs Abstract classes, defining an interface, implement interfaces, accessing implementations through interface references, extending interface.
Inner classes- Uses of inner classes, local inner classes, anonymous inner classes, static inner classes, examples.
Packages- Defining, creating and accessing a package, Understanding CLASSPATH, importing packages.
UNIT-III
Exception handling- Dealing with errors, benefits of exception handling, the classification of exceptions- exception hierarchy, checked exceptions and unchecked exceptions, usage of try, catch, throw, throws and finally, rethrowing exceptions, exception specification, built in exceptions, creating own exception sub classes.
Multithreading – Differences between multiple processes and multiple threads, thread states, creating threads, interrupting threads, thread priorities, synchronizing threads, inter-thread communication, producer consumer pattern,Exploring java.net and java.text.
UNIT-IV
Applets – Concepts of Applets, differences between applets and applications, life cycle of an applet,
types of applets, creating applets, passing parameters to applets.
Event Handling: Events, Handling mouse and keyboard events, Adapter classes.
Files- Streams- Byte streams, Character streams, Text input/output.
Files- Streams- Byte streams, Character streams, Text input/output, Binary input/output, random access file operations, File management using File class..
UNIT-V
GUI Programming with Java – AWT class hierarchy, component, container, panel, window, frame,
graphics. AWT controls: Labels, button, text field, check box, and graphics. Layout Manager – Layout manager types: border, grid and flow. Swing – Introduction, limitations of AWT, Swing vs AWT.
Java Introduction
Java is an object-oriented programming language with its runtime environment. It is a combination of features of C and C++ with some essential additional concepts. Java is well suited for both standalone and web application development and is designed to provide solutions to most of the problems faced by users of the internet era.
What is java ?
Java is an object-oriented programming language developed by Sun Microsystems, and it was released in 1995.
James Gosling initially developed Java in Sun Microsystems (which was later merged with Oracle Corporation).
Java is a set of features of C and C++. It has obtained its format from C, and OOP features from C++.
Java programs are platform independent which means they can be run on any operating system with any processor as long as the Java interpreter is available on that system.
Java code that runs on one platform does not need to be recompiled to run on another platform; it's called write once, run anywhere (WORA).
Java Virtual Machine (JVM) executes Java code, but it has been written in platform specific languages such as C/C++/ASM, etc. JVM is not written in Java and hence cannot be platform independent, and Java interpreter is a part of JVM.
Where is Java being used ?
Earlier Java was only used to design and program small computing devices, but it was later adopted as one of the platform-independent programming languages, and now according to Sun, 3 billion devices run Java. Java is one of the most important programming languages in today's IT industries.
JSP - In Java, JSP (Java Server Pages) is used to create dynamic web pages, such as in PHP and ASP.
Applets - Applets are another type of Java programs that are implemented on Internet browsers and are always run as part of a web document.
J2EE - Java 2 Enterprise Edition is a platform-independent environment that is a set of different protocols and APIs and is used by various organizations to transfer data between each other.
JavaBeans - This is a set of reusable software components that can be easily used to create new and advanced applications.
Mobile - In addition to the above technology, Java is widely used in mobile devices nowadays, many types of games and applications are being made in Java.
Types of Java Applications:
1. Web Application - Java is used to create server-side web applications. Currently, Servlet, JSP, Struts, JSF, etc. technologies are used.
2. Standalone Application - It is also known as the desktop application or window based application. An application that we need to install on every machine or server such as media player, antivirus, etc. AWT and Swing are used in java for creating standalone applications.
3. Enterprise Application - An application that is distributed in nature, such as banking applications, etc. It has the advantage of the high-level security, load balancing, and clustering. In Java, EJB is used for creating enterprise applications.
4. Mobile Application - Java is used to create application software for mobile devices. Currently, Java ME is used for building applications for small devices, and also Java is a programming language for Google Android application development.
Features of Java:
Object-Oriented - Java supports the features of object-oriented programming. Its object model is simple and easy to expand.
Platform independent - C and C++ are platform dependency languages hence the application programs written in one Operating system cannot run in any other Operating system, but in platform independence language like Java application programs written in one Operating system can able to run on any Operating system.
Simple - Java has included many features of C / C ++, which makes it easy to understand.
Secure - Java provides a wide range of protection from viruses and malicious programs. It ensures that there will be no damage and no security will be broken.
Portable - Java provides us the concept of portability. Running the same program with Java on different platforms is possible.
Robust - During the development of the program, it helps us to find possible mistakes as soon as possible.
Multi-threaded - The multithreading programming feature in Java allows you to write a program that performs several different tasks simultaneously.
Distributed - Java is designed for distributed Internet environments as it manages the TCP/IP protocol.
Popular Java Editors:
You will need a text editor to write Java programs. There is even more sophisticated IDE available in the market. But for now, you can consider one of the following:
Notepad - On Windows machine, you can use any simple text editor like Notepad (Recommended for this tutorial), TextPad.
Netbeans - is a Java IDE that is open source and free which can be downloaded from http://www.netbeans.org/index.html
Eclipse - is also a java IDE developed by the Eclipse open source community and can be downloaded from http://www.eclipse.org
Evolution of Java
The development of each programming language is based on a fact: there is a need to solve a problem that was not resolved by previous programming languages. Early programmers had to choose different programming languages, usually for various tasks, such as a specific language for a type of field. A certain language was sufficient to solve the problems of its field but was not able to solve the problems of other fields. For example, Fortran could have been used to write efficient programs for scientific problems, but it was not good for system code. Similarly, Basic was easy to understand but was not robust to write big programs; While the assembly language was powerful for writing efficient programs, but it was not easy to remember and execution. Programming languages such as Cobol, Fortran do not have structural principles. They use the Goto statement to control the flow of the program. Therefore, programs using this type of code are made up of many jumps and conditional statements that make it difficult to understand.
Therefore, C was invented in 1970, to replace the assembly language and to create a structured, effective and high-level language. The development of C was the result of the development process started with BPCL by Dennis Ritchie. BPCL is an old language developed by Martin Richard. Ken Thompson developed a language called B, which was influenced by BPCL. C is a processor-oriented programming language; it is easy to execute and understand. C became quite famous at that time because it was reliable, simple and easy to use. Though C was quite efficient and successful programming language, the complexity of the program was seeking more efficient language to solve problems. When we write a program in C, it has a limit, such as a maximum of 25000 lines of code, beyond which it can not handle the complexity. But writing and managing large programs was a demand at that time. So a new concept came.
C++ came with object-oriented programming features. C++ is the extension of C language which has been used extensively. It is a powerful modern language that includes the power and simplicity of C and the characteristics of OOP. C++ provides more functional software benefits than C. C ++ with OOP became quite famous but then a new problem arose, to control the software on different machines, a separate compiler is required for that CPU. But building a C++ compiler was quite expensive. Therefore, an efficient and easy solution was needed, and this requirement became the reason for the creation of Java, which is a portable and platform independent language.
History of Java Technology
History of Java programming language is usually associated with origin predates of the web. James Gosling, Patrick Naughton, Chris Warth, Mike Sheridan and Ed Frank initiated the Java language project in June 1991. The idea was to develop a language which was platform-independent and which could create embedded software for consumer electronic devices. It took 18 months to develop and had an initial name as Oak which was renamed to Java in 1995, due to copyright issues. Java originally developed by James Gosling at Sun Microsystems(which has since merged into Oracle Corporation) and released in 1995. JDK 1.0 released in(January 23, 1996). Java SE 10 is a current stable release of Java, and many other previous Java versions are also available.
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