From e421f2da900dbb83be097969c30894cb6cc8ba33 Mon Sep 17 00:00:00 2001
From: alevymyers <levymyersasher@gmail.com>
Date: Fri, 22 May 2026 19:28:41 -0500
Subject: [PATCH] Re-register custom events on every JFR chunk (#1740)

Co-authored-by: Andrei Pangin <1749416+apangin@users.noreply.github.com>
---
 src/converter/one/jfr/JfrReader.java | 31 +++++++++++++++++++++-------
 1 file changed, 23 insertions(+), 8 deletions(-)

diff --git a/src/converter/one/jfr/JfrReader.java b/src/converter/one/jfr/JfrReader.java
index 1f8c955e..b9503f9f 100644
--- a/src/converter/one/jfr/JfrReader.java
+++ b/src/converter/one/jfr/JfrReader.java
@@ -64,6 +64,7 @@ public class JfrReader implements Closeable {
     public final Map<String, Map<Integer, String>> enums = new HashMap<>();
 
     private final Dictionary<Constructor<? extends Event>> customEvents = new Dictionary<>();
+    private final Map<String, Class<? extends Event>> customEventsByName = new HashMap<>();
 
     private int executionSample;
     private int nativeMethodSample;
@@ -129,6 +130,11 @@ public class JfrReader implements Closeable {
     }
 
     public <E extends Event> void registerEvent(String name, Class<E> eventClass) {
+        customEventsByName.put(name, eventClass);
+        registerCustomEvent(name, eventClass);
+    }
+
+    private <E extends Event> void registerCustomEvent(String name, Class<E> eventClass) {
         JfrClass type = typesByName.get(name);
         if (type != null) {
             try {
@@ -139,6 +145,22 @@ public class JfrReader implements Closeable {
         }
     }
 
+    private void registerCustomEvents() {
+        customEvents.clear();
+
+        // The following classes are instantiated reflectively.
+        // Make sure to list them in reachability-metadata.json.
+        registerCustomEvent("jdk.CPULoad", CPULoad.class);
+        registerCustomEvent("jdk.GCHeapSummary", GCHeapSummary.class);
+        registerCustomEvent("jdk.ObjectCount", ObjectCount.class);
+        registerCustomEvent("jdk.ObjectCountAfterGC", ObjectCount.class);
+        registerCustomEvent("profiler.ProcessSample", ProcessSample.class);
+
+        for (Map.Entry<String, Class<? extends Event>> entry : customEventsByName.entrySet()) {
+            registerCustomEvent(entry.getKey(), entry.getValue());
+        }
+    }
+
     // Similar to eof(), but parses the next chunk header
     public boolean hasMoreChunks() throws IOException {
         return state == STATE_NEW_CHUNK ? readChunk(buf.position()) : state == STATE_READING;
@@ -361,6 +383,7 @@ public class JfrReader implements Closeable {
         readMeta(chunkStart + metaOffset);
         readConstantPool(chunkStart + cpOffset);
         cacheEventTypes();
+        registerCustomEvents();
 
         seek(chunkStart + CHUNK_HEADER_SIZE);
         state = STATE_READING;
@@ -616,14 +639,6 @@ public class JfrReader implements Closeable {
         cpuTimeSample = getTypeId("jdk.CPUTimeSample");
         nativeLock = getTypeId("profiler.NativeLock");
 
-        // The following classes are instantiated reflectively.
-        // Make sure to list them in reachability-metadata.json.
-        registerEvent("jdk.CPULoad", CPULoad.class);
-        registerEvent("jdk.GCHeapSummary", GCHeapSummary.class);
-        registerEvent("jdk.ObjectCount", ObjectCount.class);
-        registerEvent("jdk.ObjectCountAfterGC", ObjectCount.class);
-        registerEvent("profiler.ProcessSample", ProcessSample.class);
-
         JfrClass wallClass = typesByName.get("profiler.WallClockSample");
         hasWallTimeSpan = wallClass != null && wallClass.field("timeSpan") != null;
     }