Can Docker map multiple container ports to one host port?

Question

Based on my understanding port mapping is 1 to 1, what I don't understand is why the data structure used for port mapping in container data is like this,

"NetworkSettings": {
[...]
"Ports": {
    "8888/tcp": [
        {
            "HostIp": "0.0.0.0",
            "HostPort": "8888"
        }
    ]
}

The "8888/tcp" key maps to a list instead of single object. Thus in a Java client the data structure for Ports is like this Map<String, List<PortBinding>>, but the List here can only contain 1 element right? Or did I terribly miss something fundamental?

Answer 1

This is perfectly legal:

docker run -tid -p 8080:80 -p 8090:80 nginx

"Ports": {
            "443/tcp": null,
            "80/tcp": [
                {
                    "HostIp": "0.0.0.0",
                    "HostPort": "8090"
                },
                {
                    "HostIp": "0.0.0.0",
                    "HostPort": "8080"
                }
            ]
        }

So no, it's not 1 to 1.

Answer 2

johnharris85 's answer is correct. Here, I want to points out that you can map multiple host ports to the same container port and the opposite is impossible(except they have different IP address). Just think about how can the postman deliver things to two houses, with the same house number.