PROJECT REPORT

JAVA PROGRAMMING

INFORMATION TECHNOLOGY

TOPIC

Wrapper class and

Nesting Method

SUBMITTED BY

RAHUL SAINI

BCA IInd YEAR

Dezyne E’cole College

www.dezyneecole.com

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PROJECT REPORT

On

Java programming

At

Dezyne E’cole College

Ajmer

Submitted

Dezyne E’cole College

Towards the

Partial fulfillment

Bachelor of computer application

By

Rahul Saini

Dezyne E’cole College

106/10, civil line, Ajmer

Tel-0145-2624679

www.dezyneecole.com

2016-2017

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ACKNOWLEDGEMENT

I Rahul Saini Student Of Dezyne’ Ecole College

And Extremly Grateful To Each And Every

Individual Who Has Contribute In Sucessfull

Completion Of My Project I Express My Graditude

Towords Dezyne Ecole College For Their

Kindness.And Constant Supervision As Well As

Providing The Necessary Information And Support

Regarding The Completion Of Project.

Thank You

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SYNOPSIS

This project is a minor project made based on the theoretical concept of java this project has made our basic concept on java strong.

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Q .What is wrapper class? And explain nesting of method?

Ans.

WRAPPER CLASSES -> As point out earlier, vectors cannot handle

primitive data type types like int, float, char and double. Primitive data type’s likes may

be converted into object types by using the wrapper classes contained in the java.lang

package, following table shows the simple data types and their corresponding wrapper

class types.

Wrapper classes for converting types

Simple type Wrapper class

boolean Boolean

char Character

double Double

float Float

int Integer

long Long

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

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

Converting primitive numbers to object number using constructor method

Constructor calling Conversion action

Integer IntVal=new Integer(i) Primitive integer to Integer object.

Float FloatVal=new Float(f); Primitive float to Float object.

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

Long LongVal=new Long(l); Primitive long to Long object.

Converting object numbers to primitive number 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.long value(); Object to primitive long

double d=DoubleVal .double value(); Object to primitive double

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Converting numbers to string using to string() method

Converting string objects to numbers objects using the static method

valueOf()

Converting numeric string to primitive numbers using parsing methods.

Method calling Conversion action

str=Integer.toString(); Primitive integer to string

str=Float.toString(); Primitive float to string

str=Double.toString(); Primitive double to string

str=Long.toString(); Primitive long to string

Method calling conversion

Double val=Double valueOf(str); Converts string to Double objects.

Float val=Float valueOf(str); Converts string to Float objects.

Int val=Integer valueOf(str); Converts string to Integer objects.

Long val=Long valueOf(str); Converts string to Long objects.

Method calling Conversion action

Int i=Integer.parseInt(str); Converts string to primitive integer.

float f=Float.parseFloat(str); Converts string to primitive float.

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

Double d=Double.parseDouble(str); Converts string to primitive double.

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//Converting primitive numbers to object numbers

Output

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//Converting object numbers to primitive numbers

Output

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//Converting numbers to string

Output

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//Converting string object to numeric object

Output

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//Converting numeric string to primitive numbers

Output

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Autoboxing and unboxing->

The autoboxing and unboxing feature,introduced in j2se 5.0,facilitaes the process of

handling primitive data types in collection.we can use this feature to convert primitive

data types to wrapper class types automatically.

The compiler genrates a code implictly to convert primitive type to the corresponding

.

Wrapper class type and vice versa .

For example,consider the following statement:-

Double d=98.42;

double dbl=d.doubleValue();

Using the autoboxing and unboxing features ,we can rewrite the

above code as:-

Double d=98.42;

double dbl=d;

How the java compiler provide restriction to performe the following

conversion:-

-Convert from null type to any primitive type.

-Convert to the null type other than th identify conversion.

-Convert from any class type c to any array type if c is not object.

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//Vector without using autoboxing &unboxing

Output

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//Vectors with using autoboxing & unboxing

Output

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Nesting of method

We discussed 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,There is an 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 method.

Progarm illustrated the nesting of methods,inside a class.

The class nesting defines one constructor and two methods,namely largest() and

display().The methods display() calls the methods largest() to determine the largest of

the two number and then display the result.

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//Example of nesting of method

Output

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//Another example of nesting of method

Output

A method can call any number of methods.it is also possible for a called methods to

call another method.That is methods to call method 2,which is turn may call methods3.

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THANK YOU