Java generic field declaration

Question

In a class without generic types I want to declare a rather complex generic field similar to these:

public class Client {
    private Map

        

Answer 1

You have to somewhere introduce the type-parameter, so that you can use them in the definition for your class members.

Introducing a type-parameter can be done only on a class-level, or on a method-level. In your case, it should be on class-level:

public class Client {
    private Map, List>> classToConsumerTry1;

    private Map, List>> classToConsumerTry2;
}

This, however, implies that for both members (classToConsumerTry1 and classToConsumerTry2), T and S are the same. If you want them to be different, the you will have to get these two values from two different classes, both of which are parameterized with separate type-parameters.