def METHOD_NAME(java_home, sysprop_reader=system_property):
    """
    Determines the version number of JVM available at the provided JAVA_HOME directory.
    :param java_home: The JAVA_HOME directory to check.
    :param sysprop_reader: (Optional) only relevant for testing.
    :return: The version number of the JVM available at ``java_home``.
    """
    return sysprop_reader(java_home, "java.version")