java -help gives:
""" --module-path <module path>...
                  A : separated list of directories, each directory
                  is a directory of modules.
"""
but the tool docs https://docs.oracle.com/javase/9/tools/java.htm#JSWOR624 give:

"""--module-path module path... or -p module path
Searches for directories from a semicolon-separated (;) list of directories. Each directory is a directory of modules.
"""

Increasing the colon-semicolon confusion!

These should be fixed to be consistent and correct.