Salve a tutti,
come da titolo, jasper report mi da questo strano errore nell'eseguire il FillReport:

codice:
Exception in thread "AWT-EventQueue-0" java.lang.ClassFormatError: Extra bytes at the end of class file org/apache/commons/collections/SequencedHashMap at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClassCond(ClassLoader.java:632) at java.lang.ClassLoader.defineClass(ClassLoader.java:616) at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:141) at java.net.URLClassLoader.defineClass(URLClassLoader.java:283) at java.net.URLClassLoader.access$000(URLClassLoader.java:58) at java.net.URLClassLoader$1.run(URLClassLoader.java:197) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:190) at java.lang.ClassLoader.loadClass(ClassLoader.java:307) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301) at java.lang.ClassLoader.loadClass(ClassLoader.java:248) at net.sf.jasperreports.engine.fill.JRFillObjectFactory.setStyles (JRFillObjectFactory.java:1532) at net.sf.jasperreports.engine.fill.JRBaseFiller.loadStyles(JRBaseFiller.java: 1016) at net.sf.jasperreports.engine.fill.JRBaseFiller.fill(JRBaseFiller.java:903) at net.sf.jasperreports.engine.fill.JRBaseFiller.fill(JRBaseFiller.java:845) at net.sf.jasperreports.engine.fill.JRFiller.fillReport(JRFiller.java:58) at net.sf.jasperreports.engine.JasperFillManager.fillReport(JasperFillManager. java:417)
qualche idea?
Grazie