[PDFBOX-402] Bug when using PDF Box in a threaded environment.

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.2.0
• Component/s: Utilities
• Environment: Multi Thread usage, like in an Application Server using PDFBox to parse documents.
• Assignee: Unassigned
• Reporter: [e-mail]
• Created: 24/Jan/09 05:18
• Updated: 01/Jul/10 07:26
• Resolved: 27/Apr/10 19:13

Description

I will be using PDFBox in a thread environment

I ran the Findbugs tool (http://findbugs.sourceforge.net/)

against the package and an issue occurred in : org.apache.pdfbox.util.DateConverter;

It shows this problem in two places.

[H M STCAL] Call to static DateFormat
[STCAL_INVOKE_ON_STATIC_DATE_FORMAT_INSTANCE]

As the JavaDoc states, DateFormats are inherently unsafe for multithreaded use. The detector has found a call to an instance of DateFormat that has been obtained via a static field. This looks suspicious.

For more information on this see Sun Bug #6231579 <http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6231579> and Sun Bug #6178997 <http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6178997> .

There was only one call to the toString*(date) method
I changed the following lines to resolve the issue.

public DateConverter() {} // allows the class to be created.
// next I removed the static from the method.
public String toString( Calendar date )
{
String retval = null;
if( date != null )
{
StringBuffer buffer = new StringBuffer();
TimeZone zone = date.getTimeZone();
long offsetInMinutes = zone.getOffset(
date.getTimeInMillis() )/1000/60;
long hours = Math.abs( offsetInMinutes/60 );
long minutes = Math.abs( offsetInMinutes%60 );
buffer.append( "D:" );
// this had to be create here, it couldn't be static
// because of the bug description
SimpleDateFormat PDF_DATE_FORMAT = new SimpleDateFormat( "yyyyMMddHHmmss" );
buffer.append( PDF_DATE_FORMAT.format( date.getTime() )
Lastly, I change the call to the method in COSDictionary.
public void setDate( COSName key, Calendar date )

{ setString( key, new DateConverter().toString( date ) ); }

Issue Links

• relates to: PDFBOX-643 Date conversion errors
• relates to: PDFBOX-701 Additional date formats