--- a/src/java.base/share/classes/sun/net/www/protocol/jrt/JavaRuntimeURLConnection.java	Thu Dec 13 16:14:07 2018 +0100
+++ b/src/java.base/share/classes/sun/net/www/protocol/jrt/JavaRuntimeURLConnection.java	Thu Dec 13 15:31:05 2018 +0100
@@ -66,7 +66,7 @@
     JavaRuntimeURLConnection(URL url) throws IOException {
         super(url);
         String path = url.getPath();
-        if (path.length() == 0 || path.charAt(0) != '/')
+        if (path.isEmpty() || path.charAt(0) != '/')
             throw new MalformedURLException(url + " missing path or /");
         if (path.length() == 1) {
             this.module = null;