pub fn detect_java_version() -> Result<String, JavaError>Expand description
Detect the installed Java major version by running javac -version.
javac (not java) is used because the compiler determines what class-file
format is produced; the runtime is not guaranteed to be present. Output is
read from stdout (most JDKs) with stderr as fallback.
§Errors
Returns JavaError::Io if javac cannot be spawned or its output cannot
be parsed as a version string.