I can not use spring boot since the running an environment which is predefined by the hierarchy within the organization. The application server can support only servlet 3.0.
If consul is not possible, are there any alternatives? I need cloud configuration, actuator, and vault on plain Spring 4.3.x, without boot.
Please advise me.
Yes! Consul has nothing to do with Spring or Spring Boot. It doesn't even have anything to do with Java. We use it from Python, Java and Javascript. With Java, some of our clients are Spring Boot applications and some are not.
Consul is basically just a server with a HTTP API. There are client libraries for different languages that make it easier to use with each language. The Java Consul client has nothing to do with Spring. You could use Consul with nothing more than a basic HTTP client library in any language.
Spring does tightly integrate with Consul through Spring Cloud Consul. It isn't clear if this is part of what you were asking. Your #1 question confuses me a bit vs the title of your question.
I haven't used Hazelcast, so I can't help with your second question.
UPDATE: ...but then again, I can Google. It appears that the answer to your second answer is YES. Check this out:
https://github.com/bitsofinfo/hazelcast-consul-discovery-spi
PS: What am I missing? I just noticed that this very simple question was asked 10 hours ago. I can't believe nobody has given an answer before now.