javax.xml.validation.SchemaFactoryConfigurationError default constructor specification should specify that it creates instance with null as its detail message, now it specifies that instance is created with "no detail message":

    /**
     * Create a new <code>SchemaFactoryConfigurationError</code> with no
     * detail message.
     */

It should be similar to java.lang.Error default constructor otherwise it's not clear enough what "no detail message" means:

    /**
     * Constructs a new error with {@code null} as its detail message.
     ....