Student Dezyne E'cole College, www.dezyneecole.com Project on Wrapper Class and Nesting Method in Java

1. INFORMATION TECHNOLOGY
PROJECT REPORT
JAVA PROGRAMMING
TOPIC
WRAPPER CLASS AND
NESTED METHODS
SUBMITTED BY
RESHMA KODWANI
BCA II YEAR
DEZYNE E’COLE COLLEGE
www.dezyneecole.com
2016-2017
R

2. Project Report
On
Java Programming
At
Dezyne E’cole College
Ajmer
Submitted To
Dezyne E’cole College
Towards The
Partial Fulfillment On
BCA (Bachelor of Computer Application)
By
Reshma Kodwani
Dezyne E’cole College
106/10,Civil Lines, Ajmer
Tel-0145-2624679
Www.Dezyneecole.Com
2016-2017 Year
R

3. ACKNOWLEDGMENT
I Reshma Student Of Dezyne E’cole College, Am Extremely Grateful To
Each 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

4. Synopsis
This Project Is A Minor Project Made, Based On The Theoretical Concept
Of JAVA. This Project Has Made Our Basis Concepts On JAVA Strong.

5. 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 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 member of unique methods for handling primitive data type and
objects. They are listed in the following tables.
Constructor 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=newLong(l); Primitive long to Long Object
Converting Object Numbers to Primitive Number Using Type Value()Method
Method Calling Conversion Action
int i=IntVal intValue(); Object to primitive integer
float f=Float Val.floatValue(); Object to primitive float
long l=LongVal.longValue(); Object to primitive long
double=DoubleVal.doubleValue(); Object to primitive double

6. Converting Numbers to String Using to String()Method
Method calling Conversion Action
str=Integer toString(i); Primitive integer to string
str=Float toFloat(f); Primitive float to string
str=Double toDouble(d); Primitive double to string
str=long toLong(l); Primitive long to string
Converting String Objects to Numbers Objects Using the Static Method valueOf()
Method Calling Conversion Action
DoubleVal=Double.valueOff(str); Converts string to Double object
FloatVal=Float.valueOff(str); Converts string to Float object
IntVal=Integer.valueOff(str); Converts string to Integer object
longVal=Long.valueOff(str); Converts string to Long object
Converting Numeric String to Primitive Numbers Using Parsing Methods
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

7. Converting Primitive Numbers to Object Number

8. Converting Object Number to Primitive Number
Converting Number to String

10. Converting String Objects to Numberic Objects

11. Converting Numeric String to Primitive Number

12. Auto boxing and Unboxing
The autoboxing and unboxing features,introduced in J2SE5.0 facilitates the process of handing
primitive data type in collections.We can use this features to convert primitive data type to
wrapper class types automatically.The compiler generates the code implicitly to convert primitive
type to corresponding wrapper class type and vice-versa.For example ,consider the following
statement.
Double d_object =97.77;
Double d_primitive=d_object.doubleValue();
Using the autoboxing and unboxing feature,we can rewrite the above code as:
Double d_object =97.77;
Double d_primitive=d_object;
How,the Java compiler provides restrictions to perform the following conversions:
 Convert form null type to any primitive type.
 Convert to the null type other than the identify conversion.
 Convert from any class type C to any array type if C is not object.
Vector without using Autoboxing and Unboxing

13. Vector with using Autoboxing and Unboxing

14. Nesting Of Methods
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 ,this is an exception to this.A
method can be called by using 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().The method display()calls the
method largest() to determine the largest of the two numbers and then displays the result.
Nesting of methods

15. Another example of nesting of methods
A method can call any number of methods.it is also possible for a called method to call another
method.That is,method1 may call method 2,which in turn may call method 3.