Consider rewrite for checking non-emptiness of strings

[lyxell]

in e.g. struts bundles/admin/src/main/java/org/apache/struts2/osgi/admin/actions/ShellAction.java

we currently suggest

             errStream.close();
         }

-        output = errString != null && errString.length() > 0 ? errString : outString;
+        output = errString != null && !errString.isEmpty() ? errString : outString;
         return Action.SUCCESS;
     }

This could maybe be improved to

             errStream.close();
         }

-        output = errString != null && errString.length() > 0 ? errString : outString;
+        output = "".equals(errString) ? outString : errString;
         return Action.SUCCESS;
     }

[lyxell]

Nevermind, expressions are not equivalent