Package

This is encapsulation mechanism to group related classes and interfaces in single module. The main purposes of package are –
  •          To resolved naming conflict
  •          To improve modularity of program
  •          To provide security by preventing access of classes and interface to outside of package

 Rules –
  •          If package is available in java file then first non-comment code should be package.
  •          There can be only one package name in java file.



Note – As java naming convention, package name should be reverse of internet domain name. eg -  com.icicibank.loan housingloan
You can create class which is not in package. But it is always recommended that you should declare a class in package.

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