java.lang.ClassNotFoundException: byte cannot be found by error during Jasper Report Preview

Document ID : KB000007820
Last Modified Date : 14/02/2018
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When attempting to run a new report in Jasper Studio, the preview fails with the following error:

java.lang.ClassNotFoundException: byte cannot be found by

Jasper Studio 6.3.0 or above

After selecting or adding the fields to the reports, one of the fields type of data was incorrectly selected instead of java.lang. DATA_TYPE, it was added byte[], this type of data does not allow the report to ran since it is a not valid.


1. Open Jasper Studio and select the report with the issue.

2. in the fields folder on the bottom left, make a right click on the field and select Properties, this will birng the properties window on the right.

3. Verify the "Class" field if it has byte[] change it to java.lang.String.

4. Save the changes and test the report preview.