Question

Considering JAVA, Give an example of a class and an example of an object. Describe what a class is, what an object is, and how they are related. Use your examples to illustrate the descriptions.

Your Discussion should be at least 250 words in length, but not more than 750 words.

Answer 1

Class is a group of elements having common properties and behaviours.
And Object is an individual element among the group of elements having physical behaviours and
physical properties

1.Class:
Syntax:
[Access_Modifiers] class Class_Name [extends Super_Class_Name][implements
interface_List]
{
--- variables-----
-- methods--------
----constructors-----
----blocks------
---classes-------
----abstract classes-----
---interfaces------
---- enums--------
}

Where

Access Modifiers:

There are two types of Access modifiers

1.To define scopes to the progvramming elements, there are four types of access modifiers.

public, protected, <default> and private.

Where public and <default> are allowed for classes, protected and private are not allowed for

classes.

2.To define some extra nature to the programming elements , we have the following access

modifiers.

static, final, abstract, native, volatile, transient, synchronized, strictfp,.......

Where final, abstract and strictfp are allowed for the classes

To store entities data temporarily in java applications we need objects.
To Access the members of any particular class we need objects.
If we want to create Objects we have to use the following syntax.
Class_Name ref_Var = new Class_Name([param_List]);
EX:
class A{
----
}
A a = new A();
When JVM encounter the above instruction,JVM will perform the following actions.
1.Creating memory for the Object
2.Generating Identities for the object
3.Providing initializations inside the Object

Example of class and Object is given below:

import java.io.*;
class Check
{
String s;
Check(String s)
{
this.s=s;
}
void check()
{
String n=s.trim();
int length=n.length();
if((n.charAt(0)=='x'||n.charAt(0)=='X')&&n.charAt(length-1)=='x'||n.charAt(length-1)=='X')
{
System.out.println("Output:"+n.substring(1,length-1));
}
else if(n.charAt(0)=='x'||n.charAt(0)=='X')
{
System.out.println("Output:"+n.substring(1));
}
else if(n.charAt(length-1)=='x'||n.charAt(length-1)=='X')
{
System.out.println("Output:"+n.substring(0,length-1));
}

}

}
class Demo
{
public static void main(String args[])throws IOException        
{
BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
System.out.print("Input:");
String s=br.readLine();
Check ch=new Check(s);
ch.check();


}

}

Output:

in above program there are two classes are defined and one object is defined to access tge data of that class we can access method ,variab va, constructor from the class using object.we can not write java program withaout class we require atleast one class to write java program .