ME-306Computer Programming(Java)List Of Practical’s

1. What is Java? Define features of Java. How to differ from C & C++.2. Write a program to perform arithmetic operations.3. Write a program to print “my first java….”.4. Write a program to Swap two numbers.5. Write a program to print Floyd’s Triangle.6. Write a program to calculate a Factorial of a number.7. Write a program to print the Fibonacci Series.8. Write a program to show Exception Handling in Java.9. Write a program to show Inheritance .10. Write a program to show how to input an Array Element through Java and find the sum

of those elements.11. Write a program to demonstrate difference between Swing & AWT.12. Write a program to demonstrate AWT.13. What is the major difference between an Interface and Abstract Class.14. What is a Package? How do we tell Java that we want to use a particular package in a

file.15. What is an Applet ? How do applets differ from applications in Java.

1.What is Java? Define features of Java. How Java differ from C & C++.

A high-level programming language developed by Sun Microsystems. Java was originally called OAK, and was designed for handheld devices and set-top boxes. Oak was unsuccessful so in 1995 Sun changed the name to Java and modified the language to take advantage of the burgeoning World Wide Web.Java is an object-oriented language similar to C++, but simplified to eliminate language features that cause common programming errors. Java source code files (files with a .java extension) are compiled into a format called byte code (files with a .class extension) , which can then be executed by a Java interpreter. Compiled Java code can run on most computers because Java interpreters and runtime environments, known as Java Virtual Machines(VMs), exist for most operating systems, including UNIX, the Macintosh OS, and Windows. Byte code can also be converted directly into machine language instructions by a just-in-time compiler (JIT).Java is a general purpose programming language with a number of features that make the language well suited for use on the World Wide Web. Small Java applications are called Java applets and can be downloaded from a Web server and run on your computer by a Java-compatible Web browser, such as Netscape Navigator or Microsoft Internet Explorer.

Features Of Java1) Compiled and Interpreter:- has both Compiled and Interpreter Feature Program of java is First Compiled and Then it is must to Interpret it .First of all The Program of java is Compiled then after Compilation it creates Bytes Codes rather than Machine Language. Then After Bytes Codes are Converted into the Machine Language is Converted into the Machine Language with the help of the Interpreter So For Executing the java Program First of all it is necessary to Compile it then it must be Interpreter2) Platform Independent:- Java Language is Platform Independent means program of java is Easily transferable because after Compilation of java program bytes code will be created then we have to just transfer the Code of Byte Code to another Computer. This is not necessary for computers having same Operating System in which the code of the java is Created and Executed After Compilation of the Java Program We easily Convert the Program of the java top the another Computer for Execution.3) Object-Oriented:- We Know that is purely OOP Language that is all the Code of the java Language is Written into the classes and Objects So For This feature java is Most Popular Language because it also Supports Code Reusability, Maintainability etc.4) Robust and Secure:- The Code of java is Robust and Means first checks the reliability of the code before Execution When We trying to Convert the Higher data type into the Lower Then it Checks the Demotion of the Code the It Will Warns a User to Not to do this So it is called as RobustSecure : When We convert the Code from One Machine to Another the First Check the Code either it is Effected by the Virus or not or it Checks the Safety of the Code if code contains the Virus then it will never Executed that code on to the Machine.

5) Distributed:- Java is Distributed Language Means because the program of java is compiled onto one machine can be easily transferred to machine and Executes them on another machine because facility of Bytes Codes So java is Specially designed For Internet Users which uses the Remote Computers For Executing their Programs on local machine after transferring the Programs from Remote Computers or either from the internet.6) Simple Small and Familiar:- is a simple Language Because it contains many features of other Languages like c and C++ and Java Removes Complexity because it doesn’t use pointers, Storage Classes and Go to Statements and java Doesn’t support Multiple Inheritance7) Multithreaded and Interactive:- Java uses Multithreaded Techniques For Execution Means Like in other in Structure Languages Code is Divided into the Small Parts Like These Code of java is divided into the Smaller parts those are Executed by java in Sequence and Timing Manner this is Called as Multithreaded In this Program of java is divided into the Small parts those are Executed by Compiler of java itself Java is Called as Interactive because Code of java Supports Also CUI and Also GUI Programs8) Dynamic and Extensible Code:- Java has Dynamic and Extensible Code Means With the Help of OOPS java Provides Inheritance and With the Help of Inheritance we Reuse the Code that is Pre-defined and Also uses all the built in Functions of java and Classes9) Distributed:- Java is a distributed language which means that the program can be design to run on computer networks. Java provides an extensive library of classes for communicating ,using TCP/IP protocols such as HTTP and FTP. This makes creating network connections much easier than in C/C++. You can read and write objects on the remote sites via URL with the same ease that programmers are used to when read and write data from and to a file. This helps the programmers at remote locations to work together on the same project.10) Secure: Java was designed with security in mind. As Java is intended to be used in networked/distributor environments so it implements several security mechanisms to protect you against malicious code that might try to invade your file system.

Java differ from C & C++.

Feature C C++ Java

Programming Approach

Procedural Programming Language

Procedural, OOP, Generic Programming languages

OOP, Generic Programming languages.

Compiled Source Code

Executable in Native Code Executable in Native Code Compiled into Java byte

codeMemory management Manual Done, Manual Done, Managed, using a

garbage collector

Pointers Yes, very commonly used.

Yes, very commonly used, but some form of references available too.

No pointers; references are used instead.

Preprocessor Yes Yes NoString Type Character arrays Character arrays, objects ObjectsComplex Data Types Structures, unions Structures, unions, classes Classes

Inheritance N/A Multiple class inheritanceSingle class inheritance, multiple interface implementation

Operator Overloading N/A Yes No

Automatic coercions(Conversion)

Yes, with warnings if loss could occur

Yes, with warnings if loss could occur

Not at all if loss could occur; must cast explicitly

Variadic Parameters Yes Yes No

Goto Statement Yes Yes No

2. Write a program to perform arithemetic operations.import java.util.*;

class ArithOp{public static void main(String args[]){ int num1,num2,Add,Mul,Div,Sub; System.out.println("enter the two numbers to perform operations");Scanner sc= new Scanner(System.in);System.out.println("first number is: ");num1= sc.nextInt();System.out.println("Second number is: ");num2= sc.nextInt();

Add = num1+num2;Mul= num1 * num2;Div= num1/num2;Sub= num1-num2;System.out.println("Addition of two number is: =" +Add);System.out.println();System.out.println("Multiplication of two number is: =" +Mul);System.out.println();System.out.println("Division of two number is: =" +Div);System.out.println();System.out.println("Subtraction of two number is: =" +Sub);System.out.println();}}

Output:

3. Write a program to print “My first program….”import java.io.*;

public class FirstProg{ //This is a first simple java program. public static void main(String[] args) { System.out.println("My First JAVA program..............."); System.out.println("hello i run java first time"); }}

Output:

4. Write a program to swap to numbers.import java.util.*;

class Swap{public static void main(String[]args){int a,b,c;System.out.println("enter two variable to swap");Scanner sc = new Scanner(System.in);a=sc.nextInt();System.out.println("The variable is "+a);b=sc.nextInt();System.out.println("The variable is "+b);c=a;a=b;b=c;System.out.println("The swapped variable");System.out.println("The variable is "+a);System.out.println("The variable is "+b);}}

Output:

5. Write a program to print FLOYD’S Triangle.import java.io.*;import java.util.Scanner;

class TriangleFloyd{public static void main(String[]args){int i,j,k=1,n;Scanner sc= new Scanner(System.in);System.out.println("Enter the rows");n= sc.nextInt();for(i=1;i<=n;i++){for(j=1;j<=i;j++){System.out.print(k);k++;}System.out.println();}}}

Output:

6.Write a program to calculate a factorial of a number.import java.io.*;import java.util.Scanner;

class Factorial{public static void main(String arg[]){int n,c,fact=1;System.out.println("Enter an integer to calculate it's factorial");Scanner in=new Scanner(System.in);n=in.nextInt();if(n<0)System.out.println("Number should be non-negative");elsefor(c=1;c<=n;c++)fact=fact*c;System.out.println("Factorial of "+n+" is = "+fact); } }

Output:

7. Write a program to print a Fibonacci series.

import java.io.*;

import java.util.Scanner;class Factorial{public static void main(String arg[]){int n,c,fact=1;System.out.println("Enter an integer to calculate it's factorial");Scanner in=new Scanner(System.in);n=in.nextInt();if(n<0)System.out.println("Number should be non-negative");elsefor(c=1;c<=n;c++)fact=fact*c;System.out.println("Factorial of "+n+" is = "+fact); } }

Output:

8. Write a program to exception handling in Java.import java.io.*;import java.util.Scanner;class Exceptionhandling

{public static void main(String args[]){int a=10;int b=5,c=5;int x,y;try{x=a/(b-c);}catch(ArithmeticException e){System.out.println("Syntax error");}y=a/(b+c);System.out.println("value of y is"+y);}}

Output:

9.Write a program to show Inheritance.class Base{void show1()

{System.out.println("base show");}int x=10;}class Child extends Base{int x=20;void show(){System.out.println("child show");System.out.println("child class value "+x);System.out.println("base class value "+super.x);}}class Main{public static void main(String args[]){Child c = new Child();c.show();}}Output:

10. Write a program to show how to input array element through Java and find the sum of those element.import java.io.*;import java.util.*;

class Array{public static void main(String args[]){

int total=0;Scanner sc= new Scanner(System.in);System.out.println("enter the size of array");

int z=sc.nextInt();int x[]= new int[z];System.out.println("enter the array element");for(int i=0; i<x.length;i++)x[i]=sc.nextInt();System.out.println("array element are");for(int i=0; i<x.length;i++)

System.out.println(x[i]);for(int i=0; i<x.length;i++)total = total + x[i];

System.out.println("Sum of array element is:"+total);}}Output:

11.Write a program to demonstrate difference between Swing and AWT

import java.awt.*;import java.awt.event.*;

import javax.swing.*;class SFrame3 implements ActionListener{JTextField jt;JButton b;Button b1;JFrame f;

SFrame3(String s){f=new JFrame(s);f.setVisible(true);f.setSize(400,400);b= new JButton("Swing");b.setBounds(40,40,100,100);b1= new Button("awt");b1.setBounds(40,150,100,100);jt= new JTextField();jt.setBounds(150,40,100,100);f.add(b);f.add(b1);f.add(jt);f.setLayout(null);b.addActionListener(this);b1.addActionListener(this);f.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);}

public void actionPerformed(ActionEvent e){if(e.getSource()==b)jt.setText("Swing Example");if(e.getSource()==b1)jt.setText("awt Example");}

public static void main(String args[]){new SFrame3("MY_SWING_FRAME_WITH_EVENT");}}

Output:

12.Write a program to demonstrate AWT.

import java.awt.*;import java.awt.event.*;class EventDemo1 implements ActionListener{

Frame f;Button b,b1;TextField tf;

EventDemo1(String d){f=new Frame(d);b= new Button("ok");b1= new Button("cancel");b.setBounds(10,50,40,30);b1.setBounds(10,90,40,30);b.addActionListener(this);b1.addActionListener(this);f.add(b);f.add(b1);tf= new TextField();tf.setBounds(20,120,40,80);f.add(tf);f.setSize(400,400);f.setVisible(true);}

public void actionPerformed(ActionEvent e){if(e.getSource()==b)tf.setText("ok");elseif(e.getSource()==b1)tf.setText("cancel");}public static void main(String f[]){new EventDemo1("EventDemo1");}}

OUTPUT:

13.What is the major difference between an Interface and Abstract Class.

  Interface Abstract Class

Multiple inheritance A class may inherit several interfaces.

A class may inherit only one abstract class.

Default implementation An interface cannot provide any code, just the signature.

An abstract class can provide complete, default code and/or just the details that have to be overridden.

Access Modifiers An interface cannot have access modifiers for the subs, functions, properties etc everything is assumed as public.

An abstract class can contain access modifiers for the subs, functions, properties.

Homogeneity If various implementations only share method signatures then it is better to use Interfaces.

If various implementations are of the same kind and use common behavior or status then abstract class is better to use.

Speed Requires more time to find the actual method in the corresponding classes.

Fast

Adding functionality If we add a new method to an Interface then we have to track down all the implementations of the interface and define implementation for the new method.

If we add a new method to an abstract class then we have the option of providing default implementation and therefore all the existing code might work properly.

Fields and Constants No fields can be defined in interfaces.

An abstract class can have fields and constants defined.

Terseness The constant declarations in an interface are all presumed public static final.

Shared code can be added into an abstract class.

Constants Static final constants only, can use them without qualification in classes that implement the interface.

Both instance and static constants are possible. Both static and instance intialiser code are also possible to compute the constants.

14.What is a Package? How do we tell Java that we want to use a particular package in a file.

Packages are used in Java in order to prevent naming conflicts, to control access, to make searching/locating and usage of classes, interfaces, enumerations and annotations easier, etc.A Package can be defined as a grouping of related types (classes, interfaces, enumerations and annotations ) providing access protection and name space management.Some of the existing packages in Java are::java.lang - bundles the fundamental classesjava.io - classes for input , output functions are bundled in this packageProgrammers can define their own packages to bundle group of classes/interfaces, etc. It is a good practice to group related classes implemented by you so that a programmer can easily determine that the classes, interfaces, enumerations, annotations are related.Since the package creates a new namespace there won't be any name conflicts with names in other packages. Using packages, it is easier to provide access control and it is also easier to locate the related classes.Creating a package:When creating a package, you should choose a name for the package and put a package statement with that name at the top of every source file that contains the classes, interfaces, enumerations, and annotation types that you want to include in the package.The package statement should be the first line in the source file. There can be only one package statement in each source file, and it applies to all types in the file.If a package statement is not used then the class, interfaces, enumerations, and annotation types will be put into an unnamed package.

Example:

Let us look at an example that creates a package called animals. It is common practice to use lowercased names of packages to avoid any conflicts with the names of classes, interfaces.Put an interface in the package animals:

/* File name : Animal.java */package animals;

interface Animal { public void eat(); public void travel();}

Now, put an implementation in the same package animals:

package animals;/* File name : MammalInt.java */public class MammalInt implements Animal{ public void eat(){ System.out.println("Mammal eats"); } public void travel(){ System.out.println("Mammal travels"); } public int noOfLegs(){ return 0; } public static void main(String args[]){ MammalInt m = new MammalInt(); m.eat(); m.travel(); }}

Now, you compile these two files and put them in a sub-directory called animals and try to run as follows:

$ mkdir animals$ cp Animal. class MammalInt.class animals$ java animals/MammalIntMammal eatsMammal travels

15.What is an Applet? How it is differ from applications in Java?A Java applet is a special kind of Java program that a browser enabled with Java technology can download from the internet and run. An applet is typically embedded inside a web page and runs

in the context of a browser. An applet must be a subclass of the java.applet.Applet class. The Applet class provides the standard interface between the applet and the browser environment.Swing provides a special subclass of the Applet class called javax.swing.JApplet. The JApplet class should be used for all applets that use Swing components to construct their graphical user interfaces (GUIs).The browser's Java Plug-in software manages the lifecycle of an applet.Every Java applet must define a subclass of the Applet or JApplet class. In the Hello World applet, this subclass is called HelloWorld. The following is the source for the HelloWorld class.

import javax.swing.JApplet;import javax.swing.SwingUtilities;import javax.swing.JLabel;

public class HelloWorld extends JApplet { //Called when this applet is loaded into the browser. public void init() { //Execute a job on the event-dispatching thread; creating this applet's GUI. try { SwingUtilities.invokeAndWait(new Runnable() { public void run() { JLabel lbl = new JLabel("Hello World"); add(lbl); } } } catch (Exception e) { System.err.println("createGUI didn't complete successfully"); } }}

An applet can react to major events in the following ways: It can initialize itself. It can start running. It can stop running. It can perform a final cleanup, in preparation for being unloaded

Difference between applet and applications in JavaApplet ApplicationSmall Program Large ProgramUsed to run a program on client Browser

Can be executed on standalone computer system

Applet is portable and can be executed by any JAVA supported browser.

Need JDK, JRE, JVM installed on client machine.

Applet applications are executed in a Restricted Environment

Application can access all the resources of the computer

Applets are created by extending the java.applet.Applet

Applications are created by writing public static void main(String[] s) method.

Applet application has 5 methods which will be automatically invoked on occurrence of specific event

Application has a single start point which is main method

Example:import java.awt.*;import java.applet.*;

public class Myclass extends Applet { public void init() { } public void start() { } public void stop() {} public void destroy() {} public void paint(Graphics g) {}}

public class MyClass {public static void main(String args[]) {}}