Specification Question

[Richard Warburton]

I have noted a difference between SUN javac and ecj for a given program:

package tree;

public class Fail {
	static <T> T t() { return null; }

	public static void main(String[] args) {
		boolean b = t();
		System.out.println(b);
	}
}

This fails type checking in javac [0]:

Fail.java:6: type parameters of <T>T cannot be determined; no unique
maximal instance exists for type variable T with upper bounds
boolean,java.lang.Object
		boolean b = t();
		             ^
1 error

Under eclipse [1] it compiles, and then throws the runtime error.

Exception in thread "main" java.lang.NullPointerException
   at tree.Fail.main(Fail.java:7)

By my reading of the program, SUN javac is applying a capture on <T>
to boolean, and then realising there's no common subtype between
boolean and java.lang.Object, thus provides a compile error.  ECJ
appears to infer that java.lang.Boolean is a valid subtype of
java.lang.Object, and then apply unboxing to convert to boolean.
Throwing an exception appears correct to me under section 5.1.8 of JLS
v3.

I've skim read appropriate parts of JLS and I'm not sure which of
these behaviours corresponds to a correct JLS interpretation?  Is this
a javac bug, or an ecj bug?  Thanks for any help on the matter,
apologies if this question has already been asked somewhere.

regards,

  Richard Warburton

[0] From 1.6 release 16
[1] Galileo release