diff -r 5302477c8285 -r 85e1de070bef src/hotspot/share/classfile/classLoaderExt.cpp
--- a/src/hotspot/share/classfile/classLoaderExt.cpp	Thu Sep 12 15:46:11 2019 +0100
+++ b/src/hotspot/share/classfile/classLoaderExt.cpp	Thu Sep 12 09:59:19 2019 -0700
@@ -32,6 +32,7 @@
 #include "classfile/modules.hpp"
 #include "classfile/systemDictionaryShared.hpp"
 #include "classfile/vmSymbols.hpp"
+#include "logging/log.hpp"
 #include "memory/allocation.inline.hpp"
 #include "memory/filemap.hpp"
 #include "memory/resourceArea.hpp"
@@ -146,7 +147,7 @@
       if (found != NULL) {
         // Same behavior as jdk/src/share/classes/java/util/jar/Attributes.java
         // If duplicated entries are found, the last one is used.
-        tty->print_cr("Warning: Duplicate name in Manifest: %s.\n"
+        log_warning(cds)("Warning: Duplicate name in Manifest: %s.\n"
                       "Ensure that the manifest does not have duplicate entries, and\n"
                       "that blank lines separate individual sections in both your\n"
                       "manifest and in the META-INF/MANIFEST.MF entry in the jar file:\n%s\n", tag, jar_path);
@@ -276,7 +277,7 @@
   }
 
   if (NULL == stream) {
-    tty->print_cr("Preload Warning: Cannot find %s", class_name);
+    log_warning(cds)("Preload Warning: Cannot find %s", class_name);
     return NULL;
   }
 
@@ -295,7 +296,7 @@
                                                            THREAD);
 
   if (HAS_PENDING_EXCEPTION) {
-    tty->print_cr("Preload Error: Failed to load %s", class_name);
+    log_error(cds)("Preload Error: Failed to load %s", class_name);
     return NULL;
   }
   return result;