@Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }
        InvalidOptionConfigurationException that = (InvalidOptionConfigurationException) o;
        return Objects.equals(expectedType, that.expectedType) && Objects
            .equals(optionName, that.optionName) && Objects.equals(actualValue, that.actualValue)
            && Objects.equals(constraintFailureMessage, that.constraintFailureMessage);
    }
Get the constraint failure message, if there was a constraint failure.
common/config/src/main/java/io/apiman/common/config/options/exceptions/InvalidOptionConfigurationException.java