static Greeter defaultInstance() {
        return new Greeter() {
            @Override
            public Object greet(final boolean fail) {
                if (fail) {
                    throw new IllegalArgumentException("Failed");
                }
                return "Hello";
            }
        };
    }
Default instance greeter.

@return the greeter
support/cas-server-support-sentry/src/test/java/org/apereo/cas/sentry/Greeter.java