i have extracted the file using -xvf command.
But whenevr i try to run the demo using
java -jar jfreechart-1.0.13-demo.jar

it says "unable to access file.".also i can't understand ant compile command.can someone tell me the easiest way to install JFreechart

Did you download common lib along with jfreechart?

no,i havn't.

I have downloaded Jcommon now.Though it said installing Jcommon wasd optional.But i still face the same problem.

Please help.I'm badly stuck.

If you're using eclipse you can choose to add them as external jars.
Right click the project and select build path-> configure build path -> (Libraries tab) add external jars.

no,im not using eclipse or net beans.how to go about then?

Do you use any editor?
If you're running in cmd prompt I think you need to include the location of the jars when you run it, like: java -classpath C:\jfreechart\jfreechart.jar yourApp.java
You can also create a batch script to run it, then you won't have to specify the paths all the time.

i have set the classpath using path in environment variable.and also tried

javac -classpath C:\Documents and Settings\Administrator\jfreechart-1.0.13\lib\jfreechart-1.013.jar myapplication.java

but the compiler still does not recognise jfreechart.

What should i do?

Surron the path with "" and try again.
If that doesn't work, make sure you have all the dependencies included, separate them with ';'

This works for me:
C:\java\Playground\src> javac -classpath C:\jars\jfreechart-1.0.
12.jar;C:\jars\jcommon-1.0.15.jar DrawGraph.java