"" versus "" entries in a Tomcat Context

On The Context Container page of the Tomcat documentation, I see two sections:

• Context Parameters
• Environment Entries

The standard names for such elements is <context-param> and <env-entry>, while the Tomcat-specific names are <Parameter> and <Environment>.

Both Context Parameters and Environment Entries appear to have the same simple job of making same value available to the servlets running in that context. For example, setting a flag to communicate some condition.

➥ What is the difference between Context Parameters and Environment Entries?

➥ Why would I choose to use one instead of the other?