Cyclic static imports are very obscure. They don’t seem to be forbidden by the JLS, and javac shows weird behaviour on some horrible test cases. Figure out what to do.

---

package p;

import static q.Fred.*;

public class Bar {
public static class A extends C {}
}
—————————————
package q;

import static p.Bar.*;

public class Fred {
public static class B extends A {}
public static class C {}
}
—————————————
martin@linux:~/tmp/test/static-import> javac p/.java q/.java
p/Bar.java:6: cannot find symbol
symbol : class C
location: class p.Bar
public static class A extends C {}
^
1 error
—————————————

There are no cyclic inheritance relations here, but obviously the cyclic imports make it difficult for the type-checker to decide what to do first. In this case, the error is gone if you remove the static import and the class declaration of B, which is rather interesting.

I don’t think that the JLS forbids this for static member classes, since the code compiles if you use fully qualify names.

So, this might be a bug in javac, or the JLS should say something about cyclic static imports.

Submitted on 19 February 2006 at 03:44