tomcat:9-alpine still use openjdk 8

[chanjarster]

tomcat:9-alpine still use openjdk 8 while tomcat:9 and tomcat:9-slim use openjdk 11.

➜  ~ docker run --rm -it tomcat:9 java -version
openjdk version "11.0.12" 2021-07-20
OpenJDK Runtime Environment 18.9 (build 11.0.12+7)
OpenJDK 64-Bit Server VM 18.9 (build 11.0.12+7, mixed mode, sharing)

➜  ~ docker run --rm -it tomcat:9-slim java -version
openjdk version "11.0.3" 2019-04-16
OpenJDK Runtime Environment 18.9 (build 11.0.3+7)
OpenJDK 64-Bit Server VM 18.9 (build 11.0.3+7, mixed mode)

➜  ~ docker run --rm -it tomcat:9-alpine java -version
openjdk version "1.8.0_151"
OpenJDK Runtime Environment (IcedTea 3.6.0) (Alpine 8.151.12-r0)
OpenJDK 64-Bit Server VM (build 25.151-b12, mixed mode)

Please upgrade tomcat:9-alpine use openjdk 11 too.

[tianon]

Unfortunately, there are currently no supported Alpine variants of the tomcat image (because there are currently no supported Alpine variants of the various Java implementations).