Generics compiles and runs in Eclipse, but doesn't compile in javac

Question

Note: This is a spin-off from Comparable and Comparator contract with regards to null This code compiles and runs fine in Eclipse (`20090920-1017`) ``` import java.util.*; public class SortNull { static > Comparator nullComparableComparator() { return new Comparator() { @Override public int compare(T el1, T el2) { return el1 == null ? -1 : el2 == null ? +1 : el1.compareTo(el2); } }; } public static void main(String[] args) { List numbers = new ArrayList( Arrays.asList(3, 2, 1, null, null, 0) ); Comparator numbersComp = nullComparableComparator(); Collections.sort(numbers, numbersComp); System.out.println(numbers); // "[null, null, 0, 1, 2, 3]" List names = new ArrayList( Arrays.asList("Bob", null, "Alice", "Carol") ); Comparator namesComp = nullComparableComparator(); Collections.sort(names, namesComp); System.out.println(names); // "[null, Alice, Bob, Carol]" } } ``` And yet it doesn't compile on…

Accepted Answer

This is a confirmed bug: Bug ID 6468354. Here's an extract of relevance:

This problem is caused by the fact that sometimes javac's implementation of JLS3 15.12.2.8 ignores recursive bounds, sometimes not (as in this case). When recursive bounds contains wildcards, such bounds are included when computing uninferred type variables. This makes subsequent subtyping `test (Integer <: Comparable<? super T>` where `T` is a type-variable to be inferred).

Will be fixed after 6369605

Occured to me on WinXP with 1.6.0_13 as well. Ah well, I'll just stick using Eclipse :)

Generics compiles and runs in Eclipse, but doesn't compile in javac

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