NetBeans helps cut down on the number of JPQL errors by providing real-time checking of JPQL query syntax. If a JPQL query is typed incorrectly, a yellow light bulb will appear in the left hand margin of the NetBeans source editor and the erroneous createQuery() call will be underlined yellow, indicating the incorrect syntax (Figure 1).
Figure 1: NetBeans flags errors in JPQL query strings
Once the error is corrected, the yellow lightbulb and underline will disappear, as seen in Figure 2.
Figure 2: Errors have been repaired
This is a helpful feature because it saves the developer heart ache that would occur if an erroneous JPQL query were deployed.