Consider the following source:

import java.util.Collection;
class Test<S extends Runnable> extends ArrayList<S> {
    <T extends S & S> void test() {}
}

when compiling it using JDK 7 compiler you get 3 error messages:

TestX.java:3: cyclic inheritance involving S
    <T extends S & S> void test() {}
     ^
TestX.java:3: a type variable may not be followed by other bounds
    <T extends S & S> void test() {}
                   ^
TestX.java:2: type parameter S is not within its bound
class Test<S extends Runnable> extends ArrayList<S> {
                                                 ^
3 errors

Both the first and the last error messages are wrong: there's no cyclic inheritance involving S - only, T's bound is ill-formed. Moreover it's not true that S is not within its bound (the bound of ArrayList's type parameter is Object!).

This affects netbeans IDE badly - as multiple spourious diagnostics are generated (and NB has to patch javac to obtain the correct behavior)