Shaikh Mohammad Usman Haider ,BCA 2nd Year

BACHELOR OF COMPUTER APPLICATION Dezyne E’cole College

JAVA PROGRAMMIG TOPIC: WRAPPER CLASSES & NESTING OF METHOD

INFORMATION TECHNOLOGY

Shaikh Mohammad Usman haider

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Submitted By

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Project Report

On

Java Program

At

Dezyne E’cole College

Ajmer

Submitted To


Toward The

Practical Fulfillment On

BCA

By

Usman haider


106/10, Civil Line Lines, Ajmer

Tel – 0145- 2624679

www.dezyneecole.com

2016-2017

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ACKNOWLEDGMENT

I Shaikh Mohammad Usman Haider, Student of Dezyne E’cole College,

an Externally Grateful To Each And Every Individual Who Has Contribute

In Successful Completion of My Project

I Express My Gratitude Towards Dezyne E’cole College For Their

Guidelines And Constant Supervision As Well For 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 Concepts Of Java Strong.

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Wrapper Classes:

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

char and double. Primitive data type may be converted into object type 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 method for handling primitive

data types and object. They are listed in the following table.

Converting Primitive Number to Object Number using Constructor Method

Converting Object Number to Primitive Number using typeValue() Method

Constructor Calling Conversion Action Integer IntVal=new Integer(i); Primitive integer to integer Object

Float floatVal=new flaot(f); Primitive float to float Object

Double DoubleVal=new Double(d); Primitive Double to Double Object

Long lonfgVal=new Long(l); Primitive Long to long Object

Method Calling Conversion Action int i=IntVal.intValue(); Object to Primitive integer

float f=FloatVal.floatValue(); Object to Primitive Float

Double d=DoubleVal.doubleValue(); Object to Primitive Double

long l=LongVal.longValue(); Object to Primitive long

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Converting Number to String Using to Stirng() Method

Converting String object to Number Object Using to Static Method ValueOf()

Converting Number String To Primitive Number Using Parsing Methods

Method Calling Conversion Action Str=Integer.toStiring(i); Primitive integer to String

Str=Float.toFloat(f); Primitive Float to String

Str=Double.toDouble(d); Primitive Double to String

Str=Long.toStiring(l); Primitive Long to String

Method Calling Conversion Action DoubleVal=Double.valueOf(str); Convert string to Double Object

FloatVal=Float.valueOf(str); Convert string to Float Object

IntVal=Integer.valueOf(str); Convert string to Integer Object

LongVal.Long.valueOf(str); Convert string to Long Object

Method Calling Conversion Action Int i=integer.parseInt(str); Convert string to primitive integer

float f=Float.parseFlaot(str); Convert string to primitive Float

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

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

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Converting Primitive number to Object Number

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Converting Object Number to Primitive Number

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Converting Number to String

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Converting String Object to Numeric Object

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Converting Number String To Primitive Number

Auto Boxing and Unboxing

The auto boxing and unboxing feature, introduce in J2SE 5.0,

facilitates 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 compiling generates code implicitly

to convert primitive type to the corresponding wrapper classes type

and vice versa for example consider the following statement

Double d_object=98.42;

double d_primitive = d_object.doubleValue();

Usimg the auto boxing and unboxing feature we can rewrite the

above code as:

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Double d_object=98.42;

double d_primitive = d_object;

How the java compile provides restriction to perform the following

conversion.

1. Convert from null type to any primitive type.

2. Convert to null type other than the identify conversion

3. Convert from and 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 Method

We discussed earlier that a method of class can be called only by

an object of that class (or class itself, in the class 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 class.

Program illustrate the nesting of class:

The class nesting define one constructor and two method, namely

largest() and display(). The method display() call the method

largest() to determine the largest of the two numbers and then

displays the result.

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A method can call any number of method. It is also possible for a

called method to call another method. That is, Method 1 may call

Method 2, which in turn may call Method 3.

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Technology

Shaikh Mohammad Usman Haider ,BCA 2nd Year