Using http://www.mindswap.org/issues/file30/Input_String
Turn on pellet, and Swoop prints a stack track (and very nearly wedges itself):

apple.awt.EventQueueExceptionHandler Caught Throwable :
java.lang.RuntimeException: Cannot do reasoning with inconsistent ontologies!
java.lang.RuntimeException: Cannot do reasoning with inconsistent ontologies!
	at org.mindswap.swoop.TermsDisplay.reasonerSelChanged(TermsDisplay.java:1607)
	at org.mindswap.swoop.TermsDisplay.actionPerformed(TermsDisplay.java:1572)
	at javax.swing.JComboBox.fireActionEvent(JComboBox.java:1197)
	at javax.swing.JComboBox.setSelectedItem(JComboBox.java:561)
	at javax.swing.JComboBox.setSelectedIndex(JComboBox.java:597)
	at
javax.swing.plaf.basic.BasicComboPopup$ListMouseHandler.mouseReleased(BasicComboPopup.java:749)
	at java.awt.AWTEventMulticaster.mouseReleased(AWTEventMulticaster.java:232)
	at java.awt.Component.processMouseEvent(Component.java:5166)
	at
javax.swing.plaf.basic.BasicComboPopup$2.processMouseEvent(BasicComboPopup.java:452)
	at java.awt.Component.processEvent(Component.java:4963)
	at java.awt.Container.processEvent(Container.java:1613)
	at java.awt.Component.dispatchEventImpl(Component.java:3681)
	at java.awt.Container.dispatchEventImpl(Container.java:1671)
	at java.awt.Component.dispatchEvent(Component.java:3543)
	at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:3527)
	at java.awt.LightweightDispatcher.processMouseEvent(Container.java:3242)
	at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3172)
	at java.awt.Container.dispatchEventImpl(Container.java:1657)
	at java.awt.Window.dispatchEventImpl(Window.java:1606)
	at java.awt.Component.dispatchEvent(Component.java:3543)
	at java.awt.EventQueue.dispatchEvent(EventQueue.java:480)
	at
java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:234)
	at
java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:184)
	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:178)
	at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:170)
	at java.awt.EventDispatchThread.run(EventDispatchThread.java:100)