When processing the following command, the build waring encountered indicates that the JVM flavor 'sun' is not understood. This occurred on Ubuntu when using asdf version manager to install Erlang with the default Java version set to Java8 Open JDK.
asdf install erlang <version>
asdf version manager uses Java, by default, as a runtime build dependency, which you may disable by setting the following environment variable in your shell session prior to issuing the asdf install command:
export KERL_CONFIGURE_OPTIONS="--disable-debug --without-javac"
If you accept the default, to require Java for the asdf install command usage, you MUST ensure that the following variables are correctly set:
export JDK_HOME=/usr/bin/java
export JAVA_HOME=${JDK_HOME}
export PATH=$PATH:${JAVA_HOME}/bin
Additionally, you SHOULD only use the update-alternatives --config java command to switch between Java versions (to ensure correct symlinking to takes affect) so that the above variable settings are always correct.
Once you have satisfied these requirements, you can safely go ahead and re-process the asdf Erlang installation successfully with the following syntax:
asdf install erlang <version>
Note: In my particular case I switched from Java version 8 to Open JDK Java version 11 as I suspected that the description of the Java version I was using (ver. 8) featured the word 'sun' in the description. This change of versions eradicated the original warning message I had encountered.
