--- /dev/null	2018-06-17 23:18:20.806999507 +0800
+++ new/src/share/classes/jdk/jfr/internal/Logger.java	2019-01-29 10:59:33.965722885 +0800
@@ -0,0 +1,58 @@
+/*
+ * Copyright (c) 2016, 2019, 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
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package jdk.jfr.internal;
+
+import java.util.function.Supplier;
+
+/**
+ * JFR logger
+ *
+ */
+
+public final class Logger {
+
+    private final static int MAX_SIZE = 10000;
+
+    public static void log(LogTag logTag, LogLevel logLevel, String message) {
+        if (logTag.shouldLog(logLevel.level)) {
+            logInternal(logTag, logLevel, message);
+        }
+    }
+
+    public static void log(LogTag logTag, LogLevel logLevel, Supplier<String> messageSupplier) {
+        if (logTag.shouldLog(logLevel.level)) {
+            logInternal(logTag, logLevel, messageSupplier.get());
+        }
+    }
+
+    private static void logInternal(LogTag logTag, LogLevel logLevel, String message) {
+        if (message == null || message.length() < MAX_SIZE) {
+            JVM.log(logTag.id, logLevel.level, message);
+        } else {
+            JVM.log(logTag.id, logLevel.level, message.substring(0, MAX_SIZE));
+        }
+    }
+}