coverage: 62.087% (-0.009%) from 62.096% when pulling a119c7ed64fca38a181f20be4f3059bc4a573857 on HowtToPythonVirtualEnv into 25d438a83ff617865b7db2c344fe98dd4bf87517 on master.
Also updated test_linux.yml and code coverage.yml to fix a problem that arose on Oracle Linux 8.
Maven couldn't find the java compiler, because JAVA_HOME wasn't set.
Title says it all.