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javagenericstype-parameter

How are duplicate type parameters handled?

I have a class looks like this.

// just followed the T, U, V...
public class Some<T...., U....> {
}

And I need to add an instance method look like this.

    // not a static method
    // just followed from BiFunction<T, U, R>.class
    protected <U, R> R apply(final BiFunction<T, U, R> function,
                             final U u) {

    }

The T of the method is same as the T of the class. But the U of the method is not necessarily same as the U of the class.

Should I change one of those U?

In other words,

Are those two U same?

Solution

  • No according to the scoping rules those U are not the same. The Uof the apply method shadows the one from the class Some. To avoid confusion I would rename one of those Us.