diff -r e10a1f7aaa13 -r 8bf9268df0e2 src/java.base/share/classes/jdk/internal/module/ModulePath.java
--- a/src/java.base/share/classes/jdk/internal/module/ModulePath.java	Thu Dec 13 16:14:07 2018 +0100
+++ b/src/java.base/share/classes/jdk/internal/module/ModulePath.java	Thu Dec 13 15:31:05 2018 +0100
@@ -546,7 +546,7 @@
                     = new BufferedReader(new InputStreamReader(in, "UTF-8"));
                 String cn;
                 while ((cn = nextLine(reader)) != null) {
-                    if (cn.length() > 0) {
+                    if (!cn.isEmpty()) {
                         String pn = packageName(cn);
                         if (!packages.contains(pn)) {
                             String msg = "Provider class " + cn + " not in module";
@@ -599,7 +599,7 @@
         mn = Patterns.REPEATING_DOTS.matcher(mn).replaceAll(".");
 
         // drop leading dots
-        if (mn.length() > 0 && mn.charAt(0) == '.')
+        if (!mn.isEmpty() && mn.charAt(0) == '.')
             mn = Patterns.LEADING_DOTS.matcher(mn).replaceAll("");
 
         // drop trailing dots