Preview failing on Mac OS X

[Mathieu Bastian]

Some reports of Preview failure on OS X.

Stack trace:

java.lang.NullPointerException
 at org.gephi.desktop.preview.PreviewTopComponent.initTarget(PreviewTopComponent.java:183)
 at org.gephi.desktop.preview.PreviewTopComponent.<init>(PreviewTopComponent.java:138)
 at org.gephi.desktop.preview.PreviewTopComponent.getDefault(PreviewTopComponent.java:405)
 at org.gephi.desktop.preview.PreviewTopComponent$ResolvableHelper.readResolve(PreviewTopComponent.java:460)
 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
 at java.lang.reflect.Method.invoke(Method.java:597)
 at java.io.ObjectStreamClass.invokeReadResolve(ObjectStreamClass.java:1061)
 at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1761)
 at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1328)
 at java.io.ObjectInputStream.readObject(ObjectInputStream.java:350)
 at org.netbeans.modules.settings.convertors.XMLSettingsSupport$SettingsRecognizer.readSerial(XMLSettingsSupport.java:549)
 at org.netbeans.modules.settings.convertors.XMLSettingsSupport$SettingsRecognizer.instanceCreate(XMLSettingsSupport.java:581)
 at org.netbeans.modules.settings.convertors.SerialDataConvertor$SettingsInstance.instanceCreate(SerialDataConvertor.java:424)
 at org.netbeans.core.windows.persistence.PersistenceManager.getTopComponentPersistentForID(PersistenceManager.java:545)
 at org.netbeans.core.windows.persistence.PersistenceManager.getTopComponentForID(PersistenceManager.java:655)

[Mathieu Bastian (mathieu.bastian)]

This is what is happening...

1) It happens for 0.8 alpha (or earlier) users wich updated their Gephi to latest updates and now downloaded the 0.8 beta
2) The org.gephi.preview (PreviewImpl) module is among the modules people updated and therefore is in the dev/modules folder of people's user dir
3) When people install the 0.8 beta this folder is not wiped out, as we don't have an installer for the moment. It is cleaned by the Windows installer.
4) Due to the preview refactoring we deleted the PreviewImpl module, but made the mistake to have some of the classes with the same name and same package in the PreviewAPI.
5) Because nothing prevents the old PreviewImpl module to be loaded in the classpath of the new 0.8 beta we have a duplicate class org.gephi.preview.PreviewControllerImpl, one in the new PreviewAPI module, which is normal and one old in the PreviewImpl. That is causing the crash.

The solution is to simply delete the /users/.../Library/Application Support/gephi/ folder and it works.