Features Of Java

Chapter -2

WORKING WITH BASICS

By:A.J.Patankar

Features of Java Compiled and Interpreted Platform Independent and Portable Object Oriented Robust and Secure Distributed Dynamic and Extensible Scalability and Performance Supplementary Character Support.

How Java differs from C++ Java does not support Operator Overloading Java doesn’t have template classes Java doesn’t support multiple Inheritance. Java doesn't support global variables Java doesn’t use Pointers Destructor function is replaced by finalize() No header files in Java

Java Environment JDK comes with a collection of tools that are used for developing and running java programs includes Applet Viewer javac (Java Compiler) Java (Java Interpreter) Javap(Java disassembler) Javah (for C header files) javadoc Jdb (Java debugger)

Process of Building and Running Java Application Program Text Editor

Java Source Code

javac Java class file

java

Java Program o/p

Application Programming Interface Java Standard Library (API) includes many classes and methods grouped together in to functional packages Language Support Package Utility Package Input/Output Package. Networking Package AWT Package Applet Package

Overview of Java Java is general purpose programming language we can develop 2 types of java programs: Standard Java Application. Web Applet.

Java Virtual Machine (JVM) All language Compilers translate source code into machine code. Java Compiler (JVM) Produces an Intermediate code known as a bytecode. This Byte code can be executed on any machine or any OS to get desired output. Java Program

Bytecode

Java Compiler (JVM)

Java Interpreter

Bytecode

Machine Code

Simple Java Program File: HelloWorld.java class HelloWorld { public static void main (String args[ ]) { System.out.println(“Hello World!!”); } }

Simple Java Program public static void main (String args[ ]) : public: Access Specifier defines main as public type. (Unprotected). Static: Method belongs to the entire class and not a part of any object. void: main method does not return any value. String args[ ]:Accept Command line arguments of String type.

Simple Java Program System.out.println(“Hello World!!”);: This sentence is similar to printf() statement in C and cout<< construct of C++ Every method in Java must be part of an object println method is member of out object Which is in static data member of System class Which prints string Hello World!!.

Simple Java Program // File: RoomArea.java class Room { float length; float breadth; void getdata(float a ,float b) { length=a; breadth=b; } } Class RoomArea { public static void main (String args[ ]) { float area; Room r1=new Room(); r1.getdata(14,10) area=r1.length*r1.breadth; System.out.println(“Area=“+area); } }

Simple Java Program 1. Write a program in java to display nos. 1 to 50 with some Text message. 2. Write a program in Java to display nos. divisible by 4. 3. Write program in Java to display fibbonacci series.