Hi again!
I have uninstalled all Java versions, and installed OpenJDK 8 (1.8.0_191). After installing this OpenJDK, I now receive a message stating;
"The java binary "" couldn't be found. Please fix the java path override in the instance's settings or disable it."
I have attempted to manually set the java directory in the MultiMC settings, but it still gives this error. I have verified in the Terminal the version of Java installed as follows;
openjdk version "1.8.0_191"
OpenJDK Runtime Environment (build 1.8.0_191-8u191-b12-2ubuntu0.18.04.1-b12)
OpenJDK 64-Bit Server VM (build 25.191-b12, mixed mode)