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Q) What is a user defined package? How to create user defined package? How to make use of user defined package?




A)
->Application developers developed application specified package known as user defined package.
I.e. our own created package is known as a user defined package.
->in a user defined package, user defined class files are grouped and mode available to other application or other parts of the same application.
->user defined package creation involve 2 steps
Step1:
write a package statement in java source code
Package packagemane;

Ex:
package mypackage;

Note :
package name fallows reverse domain naming conversion
Ex:
com.mydomain

‘package’ is a keyword in java.

Step2:
compiling the source code with the fallowing system

Javac –d . sourcecode

Here

-d                  = design of .class file
“.”                 = current working directory
Sourcecode = file name
Note:
when the above command is successfully execute the fallowing things happen in the background.
1) Package name mentioned in the source code is created.
2) Java source code is compiled.
3) Class file it is stored in current working directory it is stored in the user defined package.
4) User defined package is created in the current working directory.
->to make use of the defined package, 2 steps are involved.
Step1:
in which director. User defined package is stored, place that directory in class path.
Step2:
Import the user defined package into the java application which is similar to importing a built-in package.

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