Thanks in advance
Shanti

As far as I know the only way would be to get the detailed file formats and write your own parsers using only the classes in the standard Java API - which would be very difficult.

Any sample code please ? just to read a simple file.

You can find vast amounts of sample code for reading files if you just Google for it. But if that's your level of expertise then parsing xls or pdf is an unrealistic goal in the short term.

thank you for the answer. Can you provide any links to read and print conent from pdf/xlsx files ?

also, you must understand:

Any sample code please ? just to read a simple file.

and

... without using any external jars ?

these two are very hard in conflict. either you use libraries that are supposed to perform these tasks, or you try and write your own parser, which will not be easy, and sure as hell not simple.