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

1. PROJECT
REPORT
Submitted By
Rounit Mathur
BCA II year
Java Programming
www.dezyneecole.com
Information Technology
Topic: - Wrapper Classes and Nesting of
Methods

2. Partial Fulfillment
On
Java Programming
At
Dezyne E’cole College
Submitted to
Dezyne E’cole College
Partial Fulfillment on
BCA
Bachelors of Computer Application
By
Rounit Mathur
Dezyne E’cole College
106/10, Civil Lines Ajmer
Tel-Phone - 0145-2624679
www.dezyneecole.com
2016-2017

3. Acknowledgement
I ROUNIT MATHUR STUDENT OF DEZYNE E’COLE COLLEGE,
AN 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 TO THEIR GUIDELINES AND CONSTANT
SUPERVISION AS WELL 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
THEORETICAL CONCEPTS OF JAVA. THIS PROJECT HAS
MADE OUR BASIC CONCEPTS ON JAVA STRONG.

5. Wrapper Classes
As pointed out earlier, vectors cannot handle primitive data type like int, float, char, and
double. Primitive data types may be converted into object types by using the wrapper
classes contained in the java.lang package. Following table shows the simple data type 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 objects. They are listed in the following tables.
Converting Primitive Numbers To Object Number Using Constructor Methods
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

6. Converting object Number To Primitive Numbers Using typeValue() Method
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
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=Double.toString (d); Primitive double to string
str=Long.toString (l); Primitive long to string
Converting String objects to numeric objects using the Static method ValueOf()
Method Calling Conversion Action
DoubleVal=Double.Valueof(str); Converts string to Double object
FloatVal=Float.Valueof(str); Converts string to Float object
IntVal=Integer.Valueof(str); Converts string to Integer object
LongVal=Long.Valueof(str); Converts string to Long object
Converting Numeric Strings to Primitive numbers using Parsing Methods
Method Calling Conversion Action
Int i=Integer.parseInt(str); Converts string to primitive integer
Long i=Long.parseLong(str); Converts string to primitive long

7. Converting primitive number to object number
Output:

8. Converting object number to primitive number
Output:

9. Converting number to String
Output:

10. Converting string object to numeric object
Output:

11. Converting numeric string to primitive number
Output:

12. Autoboxing and Unboxing
The autoboxing and unboxing feature, introduced in J2SE 5.0,facilities the process of
handling primitive data types in collections. We can use this feature to convert primitive data
types to wrapper class types automatically. The compiler generates a code implicitly to
convert primitive tye to the corresponding wrapper class type and vice versa. For example,
consider the following statements:
Double d_object = 98.42;
Double d_primitive = d_object.doubleValue ();
Using the autoboxing and unboxing feature, we can rewrite the above code as:
Double d_object = 98.42;
Double d_primitive = d_object;
How, the java compiler provides restrictions to perform the following conversions:
1) Convert from null type to any primitive type.
2) Convert to the null type other than the identify conversion
3) Convert from any class type C to any array type if C is not object.
Vector Without using autoboxing & unboxing
Output:

13. Vector With using autoboxing & unboxing
Output:
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,
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 methods.
Program illustrates the nesting inside a class. The class Nesting defines one
constructor and two methods, namely largest() and display(). The method display
() calls the method largest() to derermine the two numbers and then displays the
result.

14. Nesting of methods
Output:
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 method2, which in turn may call
method3.

15. Thank you