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I am working on a task in which there is an excel template which have a pivot table and an excel sheet as a datasource for that pivot table. I am updating the datasource sheet using Apache POI library in Java. If there are 1 or 2 records in the Datasource sheet, the pivot table is fine. But if there is more than 5 or 6, then it overflows from Pivot table. Attached is the screen shot for the issue I am facing. 
What can possibly the issue? And how can I get away with this? Thanks!