[PDFBOX-3404] Threads using PDFBox getting stuck when using standard 14 fonts

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.0.0, 2.0.2, 2.0.3, 3.0.0 PDFBox
• Fix Version/s: 2.0.3, 3.0.0 PDFBox
• Component/s: PDModel
• Labels: multithreading
• Assignee: Tilman Hausherr
• Reporter: Tilman Hausherr
• Created: 28/Jun/16 15:36
• Updated: 25/Mar/17 18:12
• Resolved: 08/Jul/16 15:48

Description

user prstahle reports:

We have a relatively heavily threaded application which is calling pdfbox to stamp certain
pdf files. We have been in production for a little over a week and have run into a few threads
getting stuck. The stack trace is the following:

### Thread id=34, name="dispatch_2_20160626211454_1064"
# ThreadInfo: "dispatch_2_20160626211454_1064" Id=34 RUNNABLE
# CPU: threadCpuTime=49,541,548.824 ms, threadUserTime=49,538,533.066 ms
# Contention: blockedCount=33 , blockedTime=123 ms
# Contention: lockName=null , lockOwnerId=-1, lockOwnerName=null
java.util.HashMap.put(HashMap.java:473)
java.util.HashSet.add(HashSet.java:217)
java.util.AbstractCollection.addAll(AbstractCollection.java:334)
org.apache.pdfbox.pdmodel.font.encoding.Encoding.contains(Encoding.java:109)
org.apache.pdfbox.pdmodel.font.PDType1Font.encode(PDType1Font.java:343)
org.apache.pdfbox.pdmodel.font.PDFont.encode(PDFont.java:286)
org.apache.pdfbox.pdmodel.font.PDFont.getStringWidth(PDFont.java:315)
com.tycoelectronics.emcs.stamppdf.StampEnginePDFBox.getLongestTextWidth(StampEnginePDFBox.java:1369)

We seem to be getting stuck in PDFont classes HashMap which is unsynchronized class.

We are using "PDType1Font.HELVETICA".

The problem is that for the standard 14 fonts, each font is a singleton, but its code is being used multithreaded, so we have to secure that.