What are the drawbacks with Jasper Reports? JasperReports Interview Question

• Jasper reports is not well documented. Its taking lot of time to understand which API to use for every task. But the sample provided by jasper reports is helpful in understanding. But examples for custom data-source provider is not available. so its difficult to understand the usage of custom data-source.
• Sub-reports to be troublesome as they add an extra layer of complexity to your reports.

• I think some features are missing (conditional formatting, elements with dynamic sizes)