diff -r e10a1f7aaa13 -r 8bf9268df0e2 src/java.base/share/classes/java/security/MessageDigest.java
--- a/src/java.base/share/classes/java/security/MessageDigest.java	Thu Dec 13 16:14:07 2018 +0100
+++ b/src/java.base/share/classes/java/security/MessageDigest.java	Thu Dec 13 15:31:05 2018 +0100
@@ -237,7 +237,7 @@
         throws NoSuchAlgorithmException, NoSuchProviderException
     {
         Objects.requireNonNull(algorithm, "null algorithm name");
-        if (provider == null || provider.length() == 0)
+        if (provider == null || provider.isEmpty())
             throw new IllegalArgumentException("missing provider");
         Object[] objs = Security.getImpl(algorithm, "MessageDigest", provider);
         if (objs[0] instanceof MessageDigest) {