The following trace appears when reindexing many documents:
23:35:31,405 ERROR [STDERR] close()
23:35:32,088 ERROR [STDERR] java.lang.Throwable: Warning: You did not close the PDF Document
23:35:32,088 ERROR [STDERR] at org.pdfbox.cos.COSDocument.finalize(COSDocument.java:420)
23:35:32,088 ERROR [STDERR] at java.lang.ref.Finalizer.invokeFinalizeMethod(Native Method)
23:35:32,088 ERROR [STDERR] at java.lang.ref.Finalizer.runFinalizer(Finalizer.java:83)
23:35:32,088 ERROR [STDERR] at java.lang.ref.Finalizer.access$100(Finalizer.java:14)
23:35:32,088 ERROR [STDERR] at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:160)