Problem with input content provider

I’m having a table which is binded with a contenet provider. the content provider has been created from input list of IS service.
In run time i have 500 records in the content provider and i’m showing only 25 per page. I’m using page navigation to see other page records.
While trying to access the 26th record i’m not able to access. I’m getting null pointer exception, But the contenet provider has rowcount of 500.

Please guide me on the reason why i’m not able to access the record in the second page in java code.

Thanks in advance.