diff -r 2c3cc4b01880 -r c16ac7a2eba4 src/jdk.jfr/share/classes/jdk/jfr/internal/TypeLibrary.java
--- a/src/jdk.jfr/share/classes/jdk/jfr/internal/TypeLibrary.java	Wed Oct 30 16:14:56 2019 +0100
+++ b/src/jdk.jfr/share/classes/jdk/jfr/internal/TypeLibrary.java	Wed Oct 30 19:43:52 2019 +0100
@@ -407,6 +407,7 @@
     // Purpose of this method is to mark types that are reachable
     // from registered event types. Those types that are not reachable can
     // safely be removed
+    // Returns true if type was removed
     public boolean clearUnregistered() {
         Logger.log(LogTag.JFR_METADATA, LogLevel.TRACE, "Cleaning out obsolete metadata");
         List<Type> registered = new ArrayList<>();