--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/jdk.jfr/share/classes/jdk/jfr/MetadataDefinition.java	Tue May 15 20:24:34 2018 +0200
@@ -0,0 +1,81 @@
+/*
+ * Copyright (c) 2016, 2018, 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;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+/**
+ * Meta annotation for defining new types of event metadata.
+ * <p>
+ * In the following example, a transaction event is defined with two
+ * user-defined annotations, {@code @Severity} and {@code @TransactionId}.
+ *
+ * <pre>
+ * <code>
+ *{@literal @}MetadataDefinition
+ *{@literal @}Label("Severity")
+ *{@literal @}Description("Value between 0 and 100 that indicates severity. 100 is most severe.")
+ *{@literal @}Retention(RetentionPolicy.RUNTIME)
+ *{@literal @}Target({ ElementType.TYPE })
+ * public {@literal @}interface {@literal @}Severity {
+ *   int value() default 50;
+ * }
+ *
+ *{@literal @}MetadataDefinition
+ *{@literal @}Label("Transaction Id")
+ *{@literal @}Relational
+ *{@literal @}Retention(RetentionPolicy.RUNTIME)
+ *{@literal @}Target({ ElementType.FIELD })
+ * public {@literal @}interface {@literal @}Severity {
+ * }
+ *
+ *{@literal @}Severity(80)
+ *{@literal @}Label("Transaction Blocked");
+ * class TransactionBlocked extends Event {
+ *  {@literal @}TransactionId
+ *  {@literal @}Label("Transaction");
+ *   long transactionId;
+ *
+ *  {@literal @}TransactionId
+ *  {@literal @}Label("Transaction Blocker");
+ *   long transactionId;
+ * }
+ *
+ * </code>
+ * </pre>
+ *
+ * Adding {@code @MetadataDefinition} to the declaration of {@code @Severity} and {@code @TransactionId}
+ * ensures the information is saved by Flight Recorder.
+ *
+ * @since 9
+ */
+@Retention(RetentionPolicy.RUNTIME)
+@Target({ ElementType.TYPE })
+public @interface MetadataDefinition {
+}