Karishma Dhanwani,BCA 2nd Year

Embed Size (px)

Text of Karishma Dhanwani,BCA 2nd Year

  • 1




    Wrapper class and Nesting


    Submitted by- Karishma Dhanwani

    BCA-Bechlor of Computer Application || year

    Dezyne Ecole College, www.dezyneecole.com


  • 2

    Project Report On

    Java Program


    Dezyne Ecole College


    Submitted To

    Dezyne Ecole College

    Towards The

    Partial Fullfillment on


    Bachlores Of Computer Application


    Karishma Dhanwani

    Dezyne Ecole College

    106/10 Civil Lines, Ajmer


    www.dezyne ecole.com


  • 3

    ACKNOWLEDGEMENT I Karishma Dhanwani, Student Of Dezyne Ecole College, An Extremelly

    Grantefull To Each And Every Individual Who Has Contiributed In Successful

    Comletion Of My Project. I Express My Gratitude Towards Dezyne Ecole

    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 Minar Project Made, Based On The Theoretical Concepts of

    Java This Project Has Made our Basic Cocepts On Java Strong.

  • 5

    Wrapper class :

    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 packages. Following table shows the simple data types and their corresponding wrapper class


    Simlpe 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 handeling primitive data type and object.

    They are listed in the following tables.

    Converting Primitive Numbers to Object Number Using Constructor Method

    Constructor Calling Converting 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 Number to Primitive Number Using Type Value() Method

    Method Calling Conversion Action

    int i=IntVal.intValue(); Object to Primitive integer

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

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

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

  • 6

    Converting Number 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 Object to Number Using the Static Method value of()

    Method Calling Conversion Action

    DoubleVal = Double.ValueOf(str); Converting string to Double object

    FloatVal = Float.ValueOf(str); Converting string to float object

    Integer = Integer.ValueOf(str); Converting string to Integer object

    LongVal = Long.ValueOf(str); Converting string to Long object

    Converting Numeric String to Primitive Number Using Parseing Method

    Method Calling Conversion Action

    Int l = Integer.ParseInt(str); Converting string to primitive integer

    float f = Float.ParseFloat(str); Converting string to primitive float

    long l = Long.ParseLong(str); Converting string to primitive Long

    double d = Double.ParseDouble(str); Converting string to primitive double

  • 7

    Converting Primitive Numbers to Object Numbers


  • 8

    Converting Object Numbers to Primitive Numbers


  • 9

    Converting Numbers to String


  • 10

    Converting String Object to Numeric Object


  • 11

    Converting Numeric String to Primitive Numbers


  • 12

    Auto Boxing and Unboxing

    The auto boxing and unboxing feature, introduced in J2SE 5.0, Facilitates the process of handeling

    primitive data type in collectings. We can use this feature to convert primitive data types to wrapper

    class types automatically.

    The compiler generates a code implicitly 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 = a.double value();

    Using the auto boxing and unboxing feature, we can rewrite the above code as:-

    Double d = 98.42;

    Double dbl = d;

    How, the Java compiler provides restrictions to perform the following conversion:

    Convert from 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 id C is not object.

  • 13

    Vector without using Autoboxing and Unboxing


  • 14

    Vector with Autoboxing and Unboxing


  • 15

    Nesting of Methods:-

    We dicussed 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 method

    can be called by using only its name by another method of the same class. This is known a Nesting of


    Prongram 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


  • 16

    Nesting of Methods


  • 17

    Another program of Nesting


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

    a called method to call another method. That is, method1 may call method2, which in turn may call


  • 18

    Thank you