Elasticsearch keys

Elastic Stack Elasticsearch
1

Binding key consisting of an injection type and an optional annotation. Matches the type and annotation at a point of injection. -> this is comment from elasticsearch code. Is this representation of key from key-value structure? What are key annotations and annotation types please?

2

Can you link to the code in question?

3

Sure: https://github.com/elastic/elasticsearch/blob/master/server/src/main/java/org/elasticsearch/common/inject/Key.java