<T extends Comparable<? super T>>

This is a generic type parameter declaration in Java. It specifies a type parameter T that is constrained to be a subtype of Comparable<? super T>. This means that T must be a type that can be compared to itself or to any superclass of T.

The syntax of this declaration is as follows:

- <T>: This declares a type parameter named T.
- extends Comparable<? super T>: This constrains T to be a subtype of Comparable, where the type parameter of Comparable is ? super T. This means that T must be comparable to itself or to any superclass of T.

Here is an example of how this type parameter might be used in a generic class definition:

public class MyClass<T extends Comparable<? super T>> {
    // class definition goes here
}

In this example, MyClass is a generic class that takes a type parameter T that is constrained to be a subtype of Comparable<? super T>. This means that any instance of MyClass will have access to comparison methods like compareTo() that can be used to compare objects of type T.