CODEWITHSUNDEEP
javagenerics
Durandal
Durandal

Reputation: 20069

Why the type parameter Entry is hiding the type Map.Entry?

Eclipse complains about this code with "The type parameter Entry is hiding the type Map.Entry":

import java.util.Map.Entry;

public class Test {
     static abstract class EntryIterator<Entry<K, V>> implements Iterator<K, V> {
     }
}

I don't quite understand what the problem is here - the type in question is java.util.Map.Entry. How can that shadow itself? How am I supposed to declare the inner class to make it compile?

Upvotes: 0

Views: 189

Answers (2)

kennytm
kennytm

Reputation: 523474

I think you mean

static abstract class EntryIterator<T extends Entry<?, ?>> implements Iterator<T>

This puts the constrain on the generic parameter T of EntryIterator such that it must be an Entry of something. You create an instance with

new EntryIteartor<Map.Entry<K, V>>(...);

Upvotes: 0

Jon Skeet
Jon Skeet

Reputation: 1502016

The problem is this part of the declaration:

class EntryIterator<Entry<K, V>>

That's trying to declare a type parameter called Entry<K, V> (which isn't valid). You're then saying that the class implements Iterator<K, V>, which is also invalid as Iterator only has a single type parameter.

I suspect you actually mean:

class EntryIterator<K, V> implements Iterator<Entry<K, V>>

Upvotes: 4

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