[qcnguy]

This is the philosophy used by the Java world. Big parts of the standard library are plugin-based. For example, database access (JDBC), filesystem access (NIO), cryptography (JCA). The standard library defines the interfaces and sometimes provides a default implementation, but it can be extended or replaced.

It works well, but the downside of that approach is people complaining about how abstract things are.

[goku12]

That makes sense. Just adding a clarification here. I wasn't suggesting to replace the standard library with interfaces (traits in this case). I was saying that the core library/runtime should have the interfaces for the standard library to implement some bare minimum functionalities like the allocators. Their use is more or less transparent to the application and 3rd party library developers.

Meanwhile, the public API of the selected standard library need not be abstract at all. Let's say that the bare minimum functionality expected from a 3rd party standard library is the same as the official standard library. They can just reimplement the official standard library at the minimum.