8214971: Replace use of string.equals("") with isEmpty()

Reviewed-by: jlaskey, prappo, lancea, dfuchs, redestad

src/java.rmi/share/classes/com/sun/rmi/rmid/ExecOptionPermission.java

@@ -189,7 +189,7 @@ public final class ExecOptionPermission extends Permission
         if (name == null)
             throw new NullPointerException("name can't be null");
 
-        if (name.equals("")) {
+        if (name.isEmpty()) {
             throw new IllegalArgumentException("name can't be empty");
         }