INFORMATION TECHNOLOGY

PROJECT REPORT

JAVA PROGRAMMING

TOPIC

Wrapper Class and Nesting of Methods

Submitted By

Kajal Gaharwal

Bachelors of Computer Application

2nd year

www.dezyneecole.com

Project Report

On

JAVA Program

At

Dezyne E'cole College

Ajmer

Submitted To

Dezyne E'cole College

Towards the

Partial fulfillment on

Bachelors of Computer Application

By

Kajal Gaharwal

Dezyne E'cole College

106/10, Civil Lines Ajmer

Tel-0145-2624679

www.dezyneecole.com

2016-17

ACKNOWLEDGEMENT I, Kajal Gaharwal, Student of Dezyne E'cole College, am extremely grateful to each other and every individual who has contributed in successful completion of my project. I express my gratitude towards Dezyne E'cole College for their guidance and constant supervision as well as for providing the necessary information and support regarding the completion of project.

Thank You

SYNOPSIS

This project is minor project mode, based on the theoretical concept of JAVA. This project has made our basic concept on JAVA strong.

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WRAPPER CLASS

As pointed out earlier, vectors cannot handle primitive data type like int, float, char

and double .Primitive data type may be converted into objet types by using the

wrapper classes contained in the java. Lang package. Following table shows the

simple data types and their corresponding wrapper class.

Wrapper class for converting types

Simple types Wrapper class Boolean Boolean

Char Character

Double Double Float Float

Int Integer Long Long

The wrapper class have a number of unique methods for handling primitive data

types and objects .They are listed in the following tables.

Converting primitive Numbers to Object Number Using Constructor

Method

Constructor Calling Conversion action Integer IntVal=new Integer(); Primitive integer to object Integer Float FloatVal=new Float(); Primitive float to object Float

Double DoubleVal=new Double(); Primitive double to object Double

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Converting object numbers to primitive numbers using type value ()

method

Method calling Conversion action

Int i=IntVal.int Value() Object to primitive integer float f=FloatVal.float Value() Object to primitive float

Long l=LongVal.float Value() Object to primitive long Double d=doubleVal.double Value() Object to primitive double

Converting Numbers to String using toString() method

Method calling Conversion action Str=Integer.toString(i) Primitive integer to string Str=Float.toString(f) Primitive float to string

Str=Long.toString(l) Primitive long to string

Str=Double.toString(id Primitive double to string

Converting string object to Numeric object using the static method value

Of ()

Method calling Conversion action Double val=Double.valueOf(str) Converts string to Double object

Float val=Float.valueOf(str) Converts string Float object Int val=Int.valueOf(str) Converts string to Integer object

Long val=Long.valueOf(str) Converts string to Long object

Converting Numeric string to primitive Numbers using parsing method

Method calling Conversion action Int i=Integer.parseInt(str) Converts string to primitive Integer

long l=Long.parseLong(str) Converts string to primitive Long

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Converting primitive Numbers to Object Number

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Converting object numbers to primitive Numbers

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Converting Numbers to String

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Converting String object to Numeric Object

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Converting Numeric String to Primitive numbers

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Auto boxing and unboxing

The auto boxing and unboxing feature, introduced in J2SE 5.0,facilitates

the process of handling primitive data type in collection .We use this

feature to converts primitive data type to wrapper class type

automatically .The compiler generates a code implicitly to convert

primitive type to the corresponding wrapper class type and visa -versa.

For example, consider the following statement

Double d=98.42;

Double dbl=d.doubleValue ();

Using the auto boxing and unboxing feature, we can rewrite the above

statement.

The above code as-

Double d=98.42;

Double dbl =d;

How, java compiler provides restrictions to perform the following

conversions-

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1. Converts from Null type to any primitive type.

2. Converts to the Null type other than the identify conversions.

3. Convert from any class type C to any array type if C is not object.

Vector without using auto boxing and unboxing

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Vector with using auto boxing and unboxing

NESTING OF METHODS

We discuss earlier that a method of a class can be called only by an object of that

class(or class itself ,in the case of static methods) using the dot operator ,However

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there is a exception to this .A method can be called by using only its name by

another method of the same class. This is known as nesting of methods.

Program illustrates the nesting of methods inside a class. The class nesting defines

one constructor and two methods, namely largest () and display () calls the method

largest () to determine the largest of the two numbers and then display the result.

Example-

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Another example of nesting of methods-

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A method can call any number of methods .It is called method to call another

method .That is, method 1 may call method2, which in turn may call method3.

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Thank You