From cbb3d23e19a8a893bf2fbda03e7bda4f4b7a59a6 Mon Sep 17 00:00:00 2001
From: Richard Reingruber <rrich@openjdk.org>
Date: Wed, 16 Jul 2025 06:12:07 +0000
Subject: [PATCH] 8361827: [TESTBUG]
 serviceability/HeapDump/UnmountedVThreadNativeMethodAtTop.java throws
 OutOfMemoryError

Reviewed-by: clanger, syan
---
 .../HeapDump/UnmountedVThreadNativeMethodAtTop.java    | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/test/hotspot/jtreg/serviceability/HeapDump/UnmountedVThreadNativeMethodAtTop.java b/test/hotspot/jtreg/serviceability/HeapDump/UnmountedVThreadNativeMethodAtTop.java
index 2e3925a5ca7..bb08be91dac 100644
--- a/test/hotspot/jtreg/serviceability/HeapDump/UnmountedVThreadNativeMethodAtTop.java
+++ b/test/hotspot/jtreg/serviceability/HeapDump/UnmountedVThreadNativeMethodAtTop.java
@@ -38,6 +38,7 @@ import java.util.concurrent.Callable;
 import java.util.concurrent.CountDownLatch;
 import com.sun.management.HotSpotDiagnosticMXBean;
 
+import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import static org.junit.jupiter.api.Assertions.*;
 
@@ -49,6 +50,15 @@ public class UnmountedVThreadNativeMethodAtTop {
 
     boolean done;
 
+    /**
+     * The tests accumulate previous heap dumps. Trigger GC before each test to get rid of them.
+     * This makes dumps smaller, processing faster, and avoids OOMs
+     */
+    @BeforeEach
+    void doGC() {
+        System.gc();
+    }
+
     /**
      * Test dumping the heap while a virtual thread is blocked entering a synchronized native method.
      */