--- a/src/java.base/share/classes/java/lang/invoke/MethodHandles.java	Thu Dec 13 16:14:07 2018 +0100
+++ b/src/java.base/share/classes/java/lang/invoke/MethodHandles.java	Thu Dec 13 15:31:05 2018 +0100
@@ -201,7 +201,7 @@
             throw new IllegalAccessException(callerModule + " does not read " + targetModule);
         if (targetModule.isNamed()) {
             String pn = targetClass.getPackageName();
-            assert pn.length() > 0 : "unnamed package cannot be in named module";
+            assert !pn.isEmpty() : "unnamed package cannot be in named module";
             if (!targetModule.isOpen(pn, callerModule))
                 throw new IllegalAccessException(targetModule + " does not open " + pn + " to " + callerModule);
         }