diff --git a/jdk/src/share/classes/sun/jvmstat/monitor/HostIdentifier.java b/jdk/src/share/classes/sun/jvmstat/monitor/HostIdentifier.java
index 4ac28a1034a..25bc7445b6d 100644
--- a/jdk/src/share/classes/sun/jvmstat/monitor/HostIdentifier.java
+++ b/jdk/src/share/classes/sun/jvmstat/monitor/HostIdentifier.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2020, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -112,6 +112,11 @@ private URI canonicalize(String uriString) throws URISyntaxException {
             return new URI(uriString);
         }
 
+        if (Character.isDigit(uriString.charAt(0))) {
+            // may be hostname or hostname:port since it starts with digits
+            uriString = "//" + uriString;
+        }
+
         URI u = new URI(uriString);
 
         if (u.isAbsolute()) {
diff --git a/jdk/test/sun/jvmstat/monitor/HostIdentifier/HostIdentifierCreate.java b/jdk/test/sun/jvmstat/monitor/HostIdentifier/HostIdentifierCreate.java
index 4299bf34384..486351b327b 100644
--- a/jdk/test/sun/jvmstat/monitor/HostIdentifier/HostIdentifierCreate.java
+++ b/jdk/test/sun/jvmstat/monitor/HostIdentifier/HostIdentifierCreate.java
@@ -23,7 +23,7 @@
 
 /*
  * @test
- * @bug 4990825
+ * @bug 4990825 8251155
  * @summary test that HostIdentifier objects get created as expected
  */
 
diff --git a/jdk/test/sun/jvmstat/monitor/HostIdentifier/testcases b/jdk/test/sun/jvmstat/monitor/HostIdentifier/testcases
index 28dff2cdc02..804ab14938b 100644
--- a/jdk/test/sun/jvmstat/monitor/HostIdentifier/testcases
+++ b/jdk/test/sun/jvmstat/monitor/HostIdentifier/testcases
@@ -218,4 +218,18 @@ special syntax - not a valid URI, but allowed by HostIdentifier
 <HostIdentifier> rmi://10.0.0.1:1234 </HostIdentifier>
 </testcase>
 
+<testcase id="31" HostIdentifierInput="12345">
+<description>
+Purely numeric
+</description>
+<HostIdentifier> //12345 </HostIdentifier>
+</testcase>
+
+<testcase id="32" HostIdentifierInput="12345:123">
+<description>
+Purely numeric
+</description>
+<HostIdentifier> //12345:123 </HostIdentifier>
+</testcase>
+
 </HostIdentifierTests>