--- /dev/null	2016-10-25 08:46:44.038854975 +0200
+++ new/src/share/classes/sun/evtracing/processing/MetadataStore.java	2016-10-25 10:40:44.066800620 +0200
@@ -0,0 +1,75 @@
+/*
+ * Copyright (c) 2014, 2015, Dynatrace and/or its affiliates. All rights reserved.
+ * 
+ * This file is part of the Lock Contention Tracing Subsystem for the HotSpot
+ * Virtual Machine, which is developed at Christian Doppler Laboratory on
+ * Monitoring and Evolution of Very-Large-Scale Software Systems. Please
+ * contact us at <http://mevss.jku.at/> if you need additional information
+ * or have any questions.
+ *
+ * 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.
+ *
+ * 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, see <http://www.gnu.org/licenses/>.
+ *
+ */ 
+package sun.evtracing.processing;
+
+import java.util.HashMap;
+import java.util.Map;
+
+import sun.evtracing.parser.metadata.JavaClass;
+import sun.evtracing.parser.metadata.JavaMethod;
+import sun.evtracing.parser.metadata.JavaStack;
+
+public class MetadataStore {
+
+	private static final long UNKNOWN_STACK_ID = 0;
+
+	private Map<Long, JavaClass> classes = new HashMap<>();
+	private Map<Long, JavaMethod> methods = new HashMap<>();
+	private Map<Long, JavaStack> stacks = new HashMap<>();
+
+	public JavaClass getOrAddClass(long classId) {
+		if (classId == JavaClass.SPECIAL_ID) {
+			return JavaClass.UNKNOWN;
+		}
+		return classes.computeIfAbsent(classId, k -> new JavaClass(k));
+	}
+
+	public JavaMethod getOrAddMethod(long methodId) {
+		if (methodId == JavaMethod.SPECIAL_ID) {
+			return JavaMethod.UNKNOWN;
+		}
+		return methods.computeIfAbsent(methodId, m -> new JavaMethod(m));
+	}
+
+	public JavaStack getOrAddStack(long stackId) {
+		if (stackId == UNKNOWN_STACK_ID) {
+			return JavaStack.UNKNOWN;
+		}
+		return stacks.computeIfAbsent(stackId, s -> new JavaStack());
+	}
+
+	public void purgeUnloadedClassesFrom(long classLoader) {
+		classes.values().removeIf(c -> c.classLoader() == classLoader);
+		methods.values().removeIf(m -> m.clazz().classLoader() == classLoader);
+
+		// Some stacks are not resolved immediately and thus remain unset for
+		// considerable time. One example is when a monitor is exited temporarily
+		// for Object.wait(), but the event refers to the actual lock site which can
+		// only be determined later when the monitor is actually exited. Obviously,
+		// such stacks can never be affected by class unloads.
+		// If a stack was resolved immediately, but we missed it because of a broken
+		// event order, this is a bug and we can't detect it.
+		stacks.values().removeIf(st -> st.isSet() && st.hasMethodFromClassLoader(classLoader));
+	}
+}