Sub package:
- Define a package inside other package.
- A package can have one or more sub packages.
- Creating sub package is as simple as package creation.
- Compiler creates all the required packages to generate class files in the specified location.
Examples :
- package java.operators ;
- package java.operators.arithmetic ;
Sample.java
package p1.p2;
public class Sample
{
public void fun()
{
S.o.p("p1.p2.Sample class fun…");
}
}
Access.java:
package p3.p4 ;
import p1.p2.Sample ;
class Access
{
public static void main(String[] args)
{
Sample obj = new Sample();
obj.fun();
}
}
Compile:
cmd:\> javac –d . Sample.java
cmd:\> javac –d . Access.java
Run:
cmd:\> java p3.p4.Access
Importing sub packages:
- We cannot access sub package classes by importing super package.
- We need to import sub package explicitly to access the classes belongs to that package.
- Fully Qualified Name must be used to access duplicate classes in case 2 sub packages having classes with same name.
- By importing the super package with *, we cannot access the classes of sub packages.
- We must import sub package along with super package to access sub packages classes.
- To access Scanner class, we must specify java.util.* instead of java.*
