ADDITIONAL SYSTEM INFORMATION :
Gentoo Linux
openjdk version "11" 2018-09-25
OpenJDK Runtime Environment 18.9 (build 11+28)
OpenJDK 64-Bit Server VM 18.9 (build 11+28, mixed mode)


A DESCRIPTION OF THE PROBLEM :
We render a lot of images with PDFBox with Java 1.8.0 and we want to upgrade to the current OpenJDK 11 but sadly we see some performance degradation switching over to OpenJDK. Anyone have a suggestion to remedy this issue, or can explain why it is slower?

Using the PDFBox app current release downloadable from
http://www-us.apache.org/dist/pdfbox/2.0.11/pdfbox-app-2.0.11.jar

Running the command
java -jar pdfbox-app-2.0.11.jar PDFToImage -time test.pdf

We see the following result

---------------------------------------------------------
java version "1.8.0_181"
Java(TM) SE Runtime Environment (build 1.8.0_181-b13)
Java HotSpot(TM) 64-Bit Server VM (build 25.181-b13, mixed mode)
Rendered 1 page in 2762ms
---------------------------------------------------------
openjdk version "9.0.4"
OpenJDK Runtime Environment (build 9.0.4+11)
OpenJDK 64-Bit Server VM (build 9.0.4+11, mixed mode)
Rendered 1 page in 8034ms
---------------------------------------------------------
openjdk version "10.0.2" 2018-07-17
OpenJDK Runtime Environment 18.3 (build 10.0.2+13)
OpenJDK 64-Bit Server VM 18.3 (build 10.0.2+13, mixed mode)
Rendered 1 page in 4255ms
---------------------------------------------------------
openjdk version "11" 2018-09-25
OpenJDK Runtime Environment 18.9 (build 11+28)
OpenJDK 64-Bit Server VM 18.9 (build 11+28, mixed mode)
Rendered 1 page in 4275ms
---------------------------------------------------------
openjdk version "12-ea" 2019-03-19
OpenJDK Runtime Environment 19.3 (build 12-ea+11)
OpenJDK 64-Bit Server VM 19.3 (build 12-ea+11, mixed mode)
Rendered 1 page in 4399ms

The pdf file used in this example can be downloaded from
https://drive.google.com/file/d/139wP6PDmmQ6KBTyeJTETIrplSuOUgFfG/view?usp=sharing

REGRESSION : Last worked in version 8u172

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1. Download http://www-us.apache.org/dist/pdfbox/2.0.11/pdfbox-app-2.0.11.jar
2. Download https://drive.google.com/file/d/139wP6PDmmQ6KBTyeJTETIrplSuOUgFfG/view?usp=sharing
3. Run java -jar pdfbox-app-2.0.11.jar PDFToImage -time test.pdf

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Same or better speed in newer releases of OpenJDK
ACTUAL -
OpenJDK takes 4x more time to render and OpenJDK 11 takes 2x more time.

---------- BEGIN SOURCE ----------
https://github.com/apache/pdfbox
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CUSTOMER SUBMITTED WORKAROUND :
Don't upgrade

FREQUENCY : always