PDF/A generated by JasperRports library are not valid.
Validation can by tested using tools like https://www.pdf-online.com/osa/validate.aspx
An array contains more than 8191 elements.
The value of the key Type is missing but must be StructElem.
The document does not conform to the requested standard.
The document doesn't conform to the PDF reference (missing required entries, wrong value types, etc.).
The document doesn't provide appropriate logical structure information.
The document does not conform to the PDF/A-1a standard.