temporary font files are not always be purged in multi threaded server environments like wildfly

[markus-graf]

Thousands of thousands of temporary font files can be remain in temp folder on a long running application when multiple threads using JasperReports.
See also https://community.jaspersoft.com/jasperreports-library/issues/13526

[mnboubtane]

hello ,
In wich version it's available ? i faced the same issue and i'm in 6.20
you merged it soon ?
Thanks

[Phillipus]

This is happening on Windows using JR library 6.21.4 (but not Mac or Linux).

When a report is created, several temporary font files are created in the temp folder like jr-font166714330084035962.ttf. Some are deleted when the Java process finishes, but not all. After some time there are thousands of these files.

[teodord]

You mention files remaining after Java process finishes. How exactly is the process finishing? Does it get killed? Does the JVM crash? Or does it finish properly?

[Phillipus]

You mention files remaining after Java process finishes. How exactly is the process finishing? Does it get killed? Does the JVM crash? Or does it finish properly?

It finishes properly. This is reproducible in unit tests and in our application.

What happens is that font files that are created in AwtFontManager are marked to be deleted on exit:

https://github.com/TIBCOSoftware/jasperreports/blob/4df899783f6198a3e7479948356a8a7b75294603/core/src/main/java/net/sf/jasperreports/engine/fonts/AwtFontManager.java#L79-L80

However, when Java calls its method to delete files on exit, these ones are locked by JR and cannot be deleted.

This is only on Windows (11) not Mac or Linux.

[teodord]

It finishes properly. This is reproducible in unit tests and in our application.

You mean the unit tests you have in your own application project?
Or the tests that come with our JasperReports project?

If you have a test case that consistently reproduces the issue, it would help a lot.

[Phillipus]

It finishes properly. This is reproducible in unit tests and in our application.

You mean the unit tests you have in your own application project? Or the tests that come with our JasperReports project?>

I mean our unit tests.

If you have a test case that consistently reproduces the issue, it would help a lot.

Do you have any advice on how to create a test case? Our app is Eclipse based and uses the JR library and other libs to create reports from jrxml files so it's not easy to extrapolate a simple stand-alone test.

[Phillipus]

If you have a test case that consistently reproduces the issue, it would help a lot.

@teodord I opened #505 with a test case.

[awpxx]

Deleting files on exit is definitely not a solution when using JasperReports in a server environment like Wildfly, as it typically runs for a long time. The fix proposed in this pull request resolves the issue.

[dadza]

With the fix for #505 (d313980) JasperReports is no longer creating and managing temporary files for fonts (by default).

Java/AWT will create its own temp files for fonts, and delete them whenever it sees fit after detecting that the font is no longer used/referenced.