Posts about swing

JAVA vertical gradient background panel

24 January 2015

Recently i had to create a gradient background for one of the panels in our [POS application](http://inforviegas.pt/wp-content/uploads/2010/09/VOS.jpg), so i though i'd share the code.

You need to pass the top and bottom colors of the gradient and also make sure that any panels inside this one are transparent (i.e. setOpaque(false)), otherwise they will paint above it.

import java.awt.Color; import java.awt.GradientPaint; import java.awt.Graphics; import java.awt.Graphics2D;...

JasperReports - Unsupported major.minor version 51.0

24 January 2015

Just ran into something a bit far fetched: My Jasper reports were not working in VOS, our JAVA Swing application at Inforviegas. It complained with an error along these lines: Exception in thread "AWT-EventQueue-0" java.lang.UnsupportedClassVersionError: CCClient_1334580618412_476658 : Unsupported major.minor version 51.0

The only difference from business as usual was that i changed laptops.

We are using the jasperreports-maven-plugin to compile the reports from maven. In our pom.xml files w...

NonUniqueObjectException- a different object with the same identifier value was already associated with the session

24 January 2015

If you are developing in Swing and using hibernate you might - at some point in time - run into this exception: org.hibernate.NonUniqueObjectException: a different object with the same identifier value was already associated with the session

What happened, you might ask? Well, turns out that when you close the session that created a given hibernate-managed object, this object becomes "detached" (meaning hibernate no longer has any control over it). So, when you attempt to save or update it in ...

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