Wrapper class : A class to enclosed(wrapped) the primitive
data type.
eg: Integer - it wrapp the int primitive data type.
Character - it wrap the chat data type.
int a=10;
Integer i=new Integer(a);
Java Wrapper class:
Integer,Byte,Short,Character,Boolean,Long,Float,Double.
The wrapper classes can take constructors of either the
type they are designed to wrap or of a String that can be
converted to that type. Thus the Integer class can take a
number that could be contained by an int, but an error will
occur if you try to pass a number with a floating point
component. Remember that the wrapper classes are just that
classes, they are not primitives and instances of the
wrappers can only be manipulated in the same way as any
class. You may get questions on the exam with code that
uses standard math operations to manipulate instances of
wrappers. You can of course use the + operator where it
would implicitly call the toString method, but as soon as
you see the - * or % operator, beware.
Wrapper classes are classes that are used to make primitive
data types into objects, and to make wrapped objects into
primitives because
As we know that vector in java can hold only object; but
can't directly store primitive data types, like int,float,
char, long, double. therefore we need to convert simple data
type to object. This can we done using wrapper classes.
Can we access private data outside of the class directly in
java programming language? Why There is no runtime checking
in java, which leads to access the private data directly
outside of a class?
they asked class A{}
class B{}
class c{}
all the three class saved as a single file,there is no main
method in the file
and anothe class
M.java
class m
{
psvm(String args[])
{
// here the parent class can access
}
}
There are 2 classes, 1 LandAnimal and another WaterAnimal.
There is another class Animal which wants to have the
properties of both LandAnimal and WaterAnimal. How will you
design this situation?
along with your userid / name. ThanQ
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