(As advised from this forum post -> https://forum.gephi.org/viewtopic.php?f=29&t=2233)

"A way to reproduce the bug, or a description of what you was doing. "

• After importing a sub-graph into Gephi using the Neo4j plugin with a traversal import, I am unable to either export or save a .gephi file. I have had much success in doing this procedure with other graphs using a full traversal, but I believe this is a particularly different case because the graph in which I am importing is extremely large - roughly 3 million nodes and 3 million edges. It should be noted that once this graph is in Gephi, I proceed to apply several filters in order to reduce it to a much smaller and more manageable size (which works perfectly). The data I am importing is also a mere subsection of a much larger Neo4j database - roughly 80 million nodes and edges. I suspect the ID numbers that my graph database has generated are actual Longs which may result in such an edge case. I should also note that the Data Explorer is unable to pull up the data - it has a particular problem in exporting the edges into a CSV - it omits both the source ID and destination ID portions of the data which I think is what is causing the problem!

"The configuration of your machine: Windows/Mac/Linux and system version; type of graphic card: Nvidia/ATI/integrated-to-motherboard. "

• Windows 7, 26 GB of RAM, Core I7, Nvidia Cards

"The Java stack trace if exists."
java.lang.RuntimeException: java.lang.ClassCastException: java.lang.Long cannot be cast to java.lang.String
at org.gephi.desktop.io.export.DesktopExportController$2.run(DesktopExportController.java:107)
at org.gephi.utils.longtask.api.LongTaskExecutor$RunningLongTask.run(LongTaskExecutor.java:251)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
at java.util.concurrent.FutureTask.run(FutureTask.java:166)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
at java.lang.Thread.run(Thread.java:722)
Caused by: java.lang.ClassCastException: java.lang.Long cannot be cast to java.lang.String
at org.gephi.graph.dhns.node.NodeDataImpl.getId(NodeDataImpl.java:238)
at org.gephi.io.exporter.plugin.ExporterGEXF.writeNodes(ExporterGEXF.java:371)
at org.gephi.io.exporter.plugin.ExporterGEXF.writeGraph(ExporterGEXF.java:266)
at org.gephi.io.exporter.plugin.ExporterGEXF.execute(ExporterGEXF.java:223)
at org.gephi.io.exporter.impl.ExportControllerImpl.exportFile(ExportControllerImpl.java:131)
at org.gephi.desktop.io.export.DesktopExportController$2.run(DesktopExportController.java:104)
... 7 more
Real iterations 150
Entering liquid stage...
Liquid stage completed in 444 seconds, total energy = 30899111418920960.000000
Entering expansion stage...
Expansion stage completed in 453 seconds, total energy = 77994909696.000000
Entering cool-down stage...
Real iterations 300
Entering liquid stage...
java.lang.RuntimeException: java.lang.ClassCastException: java.lang.Long cannot be cast to java.lang.String
at org.gephi.desktop.io.export.DesktopExportController$2.run(DesktopExportController.java:107)
at org.gephi.utils.longtask.api.LongTaskExecutor$RunningLongTask.run(LongTaskExecutor.java:251)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
at java.util.concurrent.FutureTask.run(FutureTask.java:166)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
at java.lang.Thread.run(Thread.java:722)
Caused by: java.lang.ClassCastException: java.lang.Long cannot be cast to java.lang.String
at org.gephi.graph.dhns.node.NodeDataImpl.getId(NodeDataImpl.java:238)
at org.gephi.io.exporter.plugin.ExporterGEXF.writeNodes(ExporterGEXF.java:371)
at org.gephi.io.exporter.plugin.ExporterGEXF.writeGraph(ExporterGEXF.java:266)
at org.gephi.io.exporter.plugin.ExporterGEXF.execute(ExporterGEXF.java:223)
at org.gephi.io.exporter.impl.ExportControllerImpl.exportFile(ExportControllerImpl.java:131)
at org.gephi.desktop.io.export.DesktopExportController$2.run(DesktopExportController.java:104)
... 7 more
SEVERE [org.netbeans.swing.outline.DefaultOutlineCellRenderer]
java.lang.ClassCastException: java.lang.Long cannot be cast to java.lang.String
at org.gephi.graph.dhns.node.NodeDataImpl.getId(NodeDataImpl.java:238)
at org.gephi.graph.dhns.node.AbstractNode.toString(AbstractNode.java:285)
at org.gephi.graph.dhns.utils.TreeNodeWrapper$TreeNodeImpl.toString(TreeNodeWrapper.java:160)
at org.openide.awt.HtmlRendererImpl.configureFrom(HtmlRendererImpl.java:197)
at org.openide.awt.HtmlRendererImpl.getTableCellRendererComponent(HtmlRendererImpl.java:131)
Caused: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
[catch] at org.netbeans.swing.outline.DefaultOutlineCellRenderer$HtmlRenderer$Renderer.getTableCellRendererComponent(DefaultOutlineCellRenderer.java:565)
at org.netbeans.swing.outline.DefaultOutlineCellRenderer.getTableCellRendererComponent(DefaultOutlineCellRenderer.java:244)
at org.netbeans.swing.etable.ETableColumn.estimatedWidth(ETableColumn.java:365)
at org.netbeans.swing.etable.ETableColumn.updatePreferredWidth(ETableColumn.java:282)
at org.netbeans.swing.etable.ETable.updatePreferredWidths(ETable.java:1764)
at org.netbeans.swing.etable.ETable.setModel(ETable.java:863)
at org.netbeans.swing.outline.Outline.setModel(Outline.java:634)
at org.gephi.desktop.datalab.NodeDataTable.refreshModel(NodeDataTable.java:258)
at org.gephi.desktop.datalab.DataTableTopComponent$8.run(DataTableTopComponent.java:471)
at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:251)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:701)
at java.awt.EventQueue.access$000(EventQueue.java:102)
at java.awt.EventQueue$3.run(EventQueue.java:662)
at java.awt.EventQueue$3.run(EventQueue.java:660)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:671)
at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:162)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:244)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:163)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:151)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:147)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:139)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:97)
SEVERE [org.openide.util.Exceptions]
java.lang.ClassCastException: java.lang.Long cannot be cast to java.lang.String
at org.gephi.graph.dhns.node.NodeDataImpl.getId(NodeDataImpl.java:238)
at org.gephi.graph.dhns.node.AbstractNode.toString(AbstractNode.java:285)
at org.gephi.graph.dhns.utils.TreeNodeWrapper$TreeNodeImpl.toString(TreeNodeWrapper.java:160)
at org.openide.awt.HtmlRendererImpl.configureFrom(HtmlRendererImpl.java:197)
at org.openide.awt.HtmlRendererImpl.getTableCellRendererComponent(HtmlRendererImpl.java:131)
Caused: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
[catch] at org.netbeans.swing.outline.DefaultOutlineCellRenderer$HtmlRenderer$Renderer.getTableCellRendererComponent(DefaultOutlineCellRenderer.java:565)
Caused: java.lang.IllegalStateException
at org.netbeans.swing.outline.DefaultOutlineCellRenderer$HtmlRenderer$Renderer.getTableCellRendererComponent(DefaultOutlineCellRenderer.java:576)
at org.netbeans.swing.outline.DefaultOutlineCellRenderer.getTableCellRendererComponent(DefaultOutlineCellRenderer.java:244)
at org.netbeans.swing.etable.ETableColumn.estimatedWidth(ETableColumn.java:365)
at org.netbeans.swing.etable.ETableColumn.updatePreferredWidth(ETableColumn.java:282)
at org.netbeans.swing.etable.ETable.updatePreferredWidths(ETable.java:1764)
at org.netbeans.swing.etable.ETable.setModel(ETable.java:863)
at org.netbeans.swing.outline.Outline.setModel(Outline.java:634)
at org.gephi.desktop.datalab.NodeDataTable.refreshModel(NodeDataTable.java:258)
[catch] at org.gephi.desktop.datalab.DataTableTopComponent$8.run(DataTableTopComponent.java:471)
at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:251)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:701)
at java.awt.EventQueue.access$000(EventQueue.java:102)
at java.awt.EventQueue$3.run(EventQueue.java:662)
at java.awt.EventQueue$3.run(EventQueue.java:660)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:671)
at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:162)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:244)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:163)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:151)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:147)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:139)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:97)
Real iterations 300
Entering liquid stage...
Liquid stage completed in 877 seconds, total energy = 24101099459837952.000000
Entering expansion stage...
Expansion stage completed in 916 seconds, total energy = 58664239104.000000
Entering cool-down stage...
Cool-down stage completed in 945 seconds, total energy = 1575196033024.000000
Entering crunch stage...
Crunch stage completed in 384 seconds, total energy = 1144025251840.000000
Entering simmer stage...
Real iterations 600
Entering liquid stage...
WARNING [org.netbeans.core.TimableEventQueue]: too much time in AWT thread org.netbeans.core.ui.sampler.SelfSamplerAction$InternalSampler@c320a3b
Liquid stage completed in 1802 seconds, total energy = 14734741081161728.000000
Entering expansion stage...
Expansion stage completed in 1814 seconds, total energy = 57823096832.000000
Entering cool-down stage...
Cool-down stage completed in 1878 seconds, total energy = 880871211008.000000
Entering crunch stage...
Crunch stage completed in 746 seconds, total energy = 873448734720.000000
Entering simmer stage...
Simmer stage completed in 1089 seconds, total energy = 95320.148438
Layout completed in 7329 seconds with 3004 iterations
SEVERE [org.netbeans.swing.outline.DefaultOutlineCellRenderer]

• This stack trace is created for each error - which results in a log file nearly 400,000 lines long.

"The log file."
https://dl.dropbox.com/u/2190/messages.log