diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach020/TEST.properties b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach020/TEST.properties
deleted file mode 100644
index 8b51b2a9115..00000000000
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach020/TEST.properties
+++ /dev/null
@@ -1,24 +0,0 @@
-#
-# Copyright (c) 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.
-#
-# 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.
-#
-
-exclusiveAccess.dirs=.
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach020/TestDescription.java b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach020/TestDescription.java
index a729aa4d28f..09d54318b60 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach020/TestDescription.java
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach020/TestDescription.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2018, 2025, 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
@@ -37,7 +37,7 @@
  *     Test scenario:
  *         - during initialization (from function Agent_OnAttach) agent starts auxiliary thread waiting on
  *         raw monitor and enables GarbageCollectionStart and GarbageCollectionFinish events
- *         - target application provokes garbage collection (calls System.gc())
+ *         - target application provokes garbage collection (calls WhiteBox.getWhiteBox().fullGC())
  *         - agent receives event GarbageCollectionStart
  *         - agent receives event GarbageCollectionFinish event and notifies waiting auxiliary thread
  *         - notified auxiliary thread notifies target application that agent finished its work
@@ -48,11 +48,13 @@
  *          /test/lib
  * @build nsk.share.aod.AODTestRunner
  *        nsk.jvmti.AttachOnDemand.attach020.attach020Target
+ * @build jdk.test.whitebox.WhiteBox
+ * @run driver jdk.test.lib.helpers.ClassFileInstaller jdk.test.whitebox.WhiteBox
  * @run main/othervm/native
  *      nsk.share.aod.AODTestRunner
  *      -jdk ${test.jdk}
  *      -target nsk.jvmti.AttachOnDemand.attach020.attach020Target
- *      -javaOpts="-XX:+UsePerfData ${test.vm.opts} ${test.java.opts}"
+ *      -javaOpts="-XX:+UsePerfData ${test.vm.opts} ${test.java.opts} -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI"
  *      -na attach020Agent00
  */
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach020/attach020Target.java b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach020/attach020Target.java
index a20cf935bae..3a52a539b82 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach020/attach020Target.java
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach020/attach020Target.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2008, 2025, 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
@@ -22,14 +22,14 @@
  */
 package nsk.jvmti.AttachOnDemand.attach020;
 
-import nsk.share.ClassUnloader;
 import nsk.share.aod.TargetApplicationWaitingAgents;
+import jdk.test.whitebox.WhiteBox;
 
 public class attach020Target extends TargetApplicationWaitingAgents {
 
     protected void targetApplicationActions() {
         log.display("Provoking garbage collection");
-        ClassUnloader.eatMemory();
+        WhiteBox.getWhiteBox().fullGC();
     }
 
     public static void main(String[] args) {
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach021/TEST.properties b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach021/TEST.properties
deleted file mode 100644
index 8b51b2a9115..00000000000
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach021/TEST.properties
+++ /dev/null
@@ -1,24 +0,0 @@
-#
-# Copyright (c) 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.
-#
-# 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.
-#
-
-exclusiveAccess.dirs=.
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach021/TestDescription.java b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach021/TestDescription.java
index 5cf7b39729b..3d8dc2f4e85 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach021/TestDescription.java
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach021/TestDescription.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2018, 2025, 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
@@ -44,11 +44,13 @@
  *          /test/lib
  * @build nsk.share.aod.AODTestRunner
  *        nsk.jvmti.AttachOnDemand.attach021.attach021Target
+ * @build jdk.test.whitebox.WhiteBox
+ * @run driver jdk.test.lib.helpers.ClassFileInstaller jdk.test.whitebox.WhiteBox
  * @run main/othervm/native
  *      nsk.share.aod.AODTestRunner
  *      -jdk ${test.jdk}
  *      -target nsk.jvmti.AttachOnDemand.attach021.attach021Target
- *      -javaOpts="-XX:+UsePerfData ${test.vm.opts} ${test.java.opts}"
+ *      -javaOpts="-XX:+UsePerfData ${test.vm.opts} ${test.java.opts} -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI"
  *      -na attach021Agent00
  */
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach021/attach021Target.java b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach021/attach021Target.java
index d287616af69..adb2c194189 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach021/attach021Target.java
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach021/attach021Target.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2008, 2025, 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
@@ -22,8 +22,8 @@
  */
 package nsk.jvmti.AttachOnDemand.attach021;
 
-import nsk.share.ClassUnloader;
 import nsk.share.aod.TargetApplicationWaitingAgents;
+import jdk.test.whitebox.WhiteBox;
 
 public class attach021Target extends TargetApplicationWaitingAgents {
 
@@ -51,7 +51,7 @@ protected void targetApplicationActions() throws Throwable {
         try {
             if (createTaggedObject()) {
                 log.display("Provoking GC");
-                ClassUnloader.eatMemory();
+                WhiteBox.getWhiteBox().fullGC();
             }
         } finally {
             shutdownAgent();
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach022/TEST.properties b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach022/TEST.properties
deleted file mode 100644
index 8b51b2a9115..00000000000
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach022/TEST.properties
+++ /dev/null
@@ -1,24 +0,0 @@
-#
-# Copyright (c) 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.
-#
-# 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.
-#
-
-exclusiveAccess.dirs=.
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach022/TestDescription.java b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach022/TestDescription.java
index 49b47585749..5875f7a0f50 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach022/TestDescription.java
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach022/TestDescription.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2018, 2025, 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
@@ -47,11 +47,13 @@
  *          /test/lib
  * @build nsk.share.aod.AODTestRunner
  *        nsk.jvmti.AttachOnDemand.attach022.attach022Target
+ * @build jdk.test.whitebox.WhiteBox
+ * @run driver jdk.test.lib.helpers.ClassFileInstaller jdk.test.whitebox.WhiteBox
  * @run main/othervm/native
  *      nsk.share.aod.AODTestRunner
  *      -jdk ${test.jdk}
  *      -target nsk.jvmti.AttachOnDemand.attach022.attach022Target
- *      -javaOpts="-XX:+UsePerfData ${test.vm.opts} ${test.java.opts}"
+ *      -javaOpts="-XX:+UsePerfData ${test.vm.opts} ${test.java.opts} -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI"
  *      -na attach022Agent00
  */
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach022/attach022Target.java b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach022/attach022Target.java
index eb80c0c2a4c..3324855e622 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach022/attach022Target.java
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/AttachOnDemand/attach022/attach022Target.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2008, 2025, 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
@@ -22,8 +22,8 @@
  */
 package nsk.jvmti.AttachOnDemand.attach022;
 
-import nsk.share.ClassUnloader;
 import nsk.share.aod.TargetApplicationWaitingAgents;
+import jdk.test.whitebox.WhiteBox;
 
 class ClassForAllocationEventsTest {
 
@@ -47,7 +47,7 @@ protected void targetApplicationActions() throws Throwable {
             }
 
             log.display("Provoking GC");
-            ClassUnloader.eatMemory();
+            WhiteBox.getWhiteBox().fullGC();
         } finally {
             if (!shutdownAgent(TEST_ALLOCATION_NUMBER)) {
                 setStatusFailed("Error happened during agent work, see error messages for details");
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionFinish/gcfinish001.java b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionFinish/gcfinish001.java
index 433ee607d7c..3e25000a2fb 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionFinish/gcfinish001.java
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionFinish/gcfinish001.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2025, 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
@@ -27,6 +27,7 @@
 import java.math.*;
 
 import nsk.share.*;
+import jdk.test.whitebox.WhiteBox;
 
 /**
  * This test exercises the JVMTI event <code>GarbageCollectionFinish</code>.
@@ -63,7 +64,7 @@ public static int run(String argv[], PrintStream out) {
     private int runThis(String argv[], PrintStream out) {
         try {
             for (int i=0; i<ITERATIONS; i++)
-                ClassUnloader.eatMemory(); // provoke garbage collecting
+                WhiteBox.getWhiteBox().fullGC(); // provoke garbage collecting
         } catch (OutOfMemoryError e) {
             // ignoring
         }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionFinish/gcfinish001/TEST.properties b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionFinish/gcfinish001/TEST.properties
deleted file mode 100644
index 8b51b2a9115..00000000000
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionFinish/gcfinish001/TEST.properties
+++ /dev/null
@@ -1,24 +0,0 @@
-#
-# Copyright (c) 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.
-#
-# 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.
-#
-
-exclusiveAccess.dirs=.
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionFinish/gcfinish001/TestDescription.java b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionFinish/gcfinish001/TestDescription.java
index f43b67b7d47..5326313a11e 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionFinish/gcfinish001/TestDescription.java
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionFinish/gcfinish001/TestDescription.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2018, 2025, 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
@@ -40,8 +40,11 @@
  *
  * @library /vmTestbase
  *          /test/lib
+ * @build jdk.test.whitebox.WhiteBox
+ * @run driver jdk.test.lib.helpers.ClassFileInstaller jdk.test.whitebox.WhiteBox
  * @run main/othervm/native
  *      -XX:-UseGCOverheadLimit
+ *      -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI
  *      -agentlib:gcfinish001=-waittime=5
  *      nsk.jvmti.GarbageCollectionFinish.gcfinish001
  */
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionStart/gcstart001.java b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionStart/gcstart001.java
index 90521649b76..f5be28b7298 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionStart/gcstart001.java
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionStart/gcstart001.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2025, 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
@@ -27,6 +27,7 @@
 import java.math.*;
 
 import nsk.share.*;
+import jdk.test.whitebox.WhiteBox;
 
 /**
  * This test exercises the JVMTI event <code>GarbageCollectionStart</code>.
@@ -63,13 +64,7 @@ public static int run(String argv[], PrintStream out) {
     }
 
     private int runThis(String argv[], PrintStream out) {
-        try {
-            for (int i=0; i<ITERATIONS; i++)
-                ClassUnloader.eatMemory(); // provoke garbage collecting
-        } catch (OutOfMemoryError e) {
-            // ignoring
-        }
-
+        WhiteBox.getWhiteBox().fullGC(); // provoke garbage collecting
         return Consts.TEST_PASSED;
     }
 }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionStart/gcstart001/TEST.properties b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionStart/gcstart001/TEST.properties
deleted file mode 100644
index 8b51b2a9115..00000000000
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionStart/gcstart001/TEST.properties
+++ /dev/null
@@ -1,24 +0,0 @@
-#
-# Copyright (c) 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.
-#
-# 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.
-#
-
-exclusiveAccess.dirs=.
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionStart/gcstart001/TestDescription.java b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionStart/gcstart001/TestDescription.java
index 6f924691ff1..7cf879f1d22 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionStart/gcstart001/TestDescription.java
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionStart/gcstart001/TestDescription.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2018, 2025, 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
@@ -40,8 +40,11 @@
  *
  * @library /vmTestbase
  *          /test/lib
+ * @build jdk.test.whitebox.WhiteBox
+ * @run driver jdk.test.lib.helpers.ClassFileInstaller jdk.test.whitebox.WhiteBox
  * @run main/othervm/native
  *      -XX:-UseGCOverheadLimit
+ *      -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI
  *      -agentlib:gcstart001=-waittime=5
  *      nsk.jvmti.GarbageCollectionStart.gcstart001
  */
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionStart/gcstart002.java b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionStart/gcstart002.java
index 907758b4f7a..3b237329d77 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionStart/gcstart002.java
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionStart/gcstart002.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2025, 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
@@ -27,6 +27,7 @@
 import java.math.*;
 
 import nsk.share.*;
+import jdk.test.whitebox.WhiteBox;
 
 /**
  * This test exercises the JVMTI event <code>GarbageCollectionStart</code>.
@@ -61,13 +62,7 @@ public static int run(String argv[], PrintStream out) {
     }
 
     private int runThis(String argv[], PrintStream out) {
-        try {
-            for (int i=0; i<ITERATIONS; i++)
-                ClassUnloader.eatMemory(); // provoke garbage collecting
-        } catch (OutOfMemoryError e) {
-            // ignoring
-        }
-
+        WhiteBox.getWhiteBox().fullGC(); // provoke garbage collecting
         return Consts.TEST_PASSED;
     }
 }
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionStart/gcstart002/TEST.properties b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionStart/gcstart002/TEST.properties
deleted file mode 100644
index 8b51b2a9115..00000000000
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionStart/gcstart002/TEST.properties
+++ /dev/null
@@ -1,24 +0,0 @@
-#
-# Copyright (c) 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.
-#
-# 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.
-#
-
-exclusiveAccess.dirs=.
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionStart/gcstart002/TestDescription.java b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionStart/gcstart002/TestDescription.java
index 85c42fcf597..c81cc81c930 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionStart/gcstart002/TestDescription.java
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/GarbageCollectionStart/gcstart002/TestDescription.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2018, 2025, 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
@@ -40,8 +40,11 @@
  *
  * @library /vmTestbase
  *          /test/lib
+ * @build jdk.test.whitebox.WhiteBox
+ * @run driver jdk.test.lib.helpers.ClassFileInstaller jdk.test.whitebox.WhiteBox
  * @run main/othervm/native
  *      -XX:-UseGCOverheadLimit
+ *      -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI
  *      -agentlib:gcstart002=-waittime=5
  *      nsk.jvmti.GarbageCollectionStart.gcstart002
  */
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP12/ap12t001.java b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP12/ap12t001.java
index fa87e6aa33e..3b9a4a1c668 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP12/ap12t001.java
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP12/ap12t001.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2025, 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
@@ -28,10 +28,9 @@
 
 import nsk.share.*;
 import nsk.share.jvmti.*;
+import jdk.test.whitebox.WhiteBox;
 
 public class ap12t001 extends DebugeeClass {
-    /* number of interations to provoke garbage collecting */
-    final static int GC_TRYS = 1;
 
     public static void main(String[] argv) {
         argv = nsk.share.jvmti.JVMTITest.commonInit(argv);
@@ -70,9 +69,8 @@ private int runThis(String argv[], PrintStream out) {
         log.display("References are ready for garbage collection");
         status = checkStatus(status);
 
-        // Provoke OutOfMemoryError in order to clear all soft references
-        for (int i= 0; i < GC_TRYS; i++)
-            ClassUnloader.eatMemory();
+        // Provoke fullgc in order to clear all soft references
+        WhiteBox.getWhiteBox().fullGC();
         log.display("GC called");
         flushObjectFreeEvents();
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP12/ap12t001/TEST.properties b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP12/ap12t001/TEST.properties
deleted file mode 100644
index 8b51b2a9115..00000000000
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP12/ap12t001/TEST.properties
+++ /dev/null
@@ -1,24 +0,0 @@
-#
-# Copyright (c) 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.
-#
-# 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.
-#
-
-exclusiveAccess.dirs=.
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP12/ap12t001/TestDescription.java b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP12/ap12t001/TestDescription.java
index e4830b82c86..48fc66927a3 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP12/ap12t001/TestDescription.java
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/allocation/AP12/ap12t001/TestDescription.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2018, 2025, 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
@@ -39,9 +39,12 @@
  * @library /vmTestbase
  *          /test/lib
  * @build nsk.jvmti.scenarios.allocation.AP12.ap12t001
+ * @build jdk.test.whitebox.WhiteBox
+ * @run driver jdk.test.lib.helpers.ClassFileInstaller jdk.test.whitebox.WhiteBox
  * @run main/othervm/native
  *      -agentlib:ap12t001=-waittime=5,-verbose
  *      -XX:-UseGCOverheadLimit
+ *      -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI
  *      nsk.jvmti.scenarios.allocation.AP12.ap12t001
  */
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t002.java b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t002.java
index ebd662aa919..8cde4f72710 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t002.java
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t002.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2025, 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
@@ -27,6 +27,7 @@
 
 import nsk.share.*;
 import nsk.share.jvmti.*;
+import jdk.test.whitebox.WhiteBox;
 
 public class em02t002 extends DebugeeClass {
 
@@ -61,7 +62,7 @@ public int runIt(String argv[], PrintStream out) {
 
             logger.display("generating events");
 
-            ClassUnloader.eatMemory();
+            WhiteBox.getWhiteBox().fullGC();
 
             int currStatus = em02t002.checkStatus(Consts.TEST_PASSED);
             if (currStatus != Consts.TEST_PASSED)
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t002/TEST.properties b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t002/TEST.properties
deleted file mode 100644
index 8b51b2a9115..00000000000
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t002/TEST.properties
+++ /dev/null
@@ -1,24 +0,0 @@
-#
-# Copyright (c) 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.
-#
-# 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.
-#
-
-exclusiveAccess.dirs=.
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t002/TestDescription.java b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t002/TestDescription.java
index a9edca92190..b6dcf409b6e 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t002/TestDescription.java
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t002/TestDescription.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, 2021, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2018, 2025, 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
@@ -71,9 +71,12 @@
  *
  * @library /vmTestbase
  *          /test/lib
+ * @build jdk.test.whitebox.WhiteBox
+ * @run driver jdk.test.lib.helpers.ClassFileInstaller jdk.test.whitebox.WhiteBox
  * @run main/othervm/native
  *      -agentlib:em02t002=-waittime=5
  *      -XX:-UseGCOverheadLimit
+ *      -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI
  *      nsk.jvmti.scenarios.events.EM02.em02t002
  */
 
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t006.java b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t006.java
index 4521a190eb3..39f153c6f77 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t006.java
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t006.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2004, 2025, 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
@@ -27,6 +27,7 @@
 
 import nsk.share.*;
 import nsk.share.jvmti.*;
+import jdk.test.whitebox.WhiteBox;
 
 public class em02t006 extends DebugeeClass {
 
@@ -62,7 +63,7 @@ public int runIt(String args[], PrintStream out) {
             }
 
             logger.display("ObjectFree:: Provoke JVMTI_EVENT_OBJECT_FREE");
-            ClassUnloader.eatMemory();
+            WhiteBox.getWhiteBox().fullGC();
 
             if (checkStatus(Consts.TEST_PASSED) == Consts.TEST_FAILED) {
                 status = Consts.TEST_FAILED;
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t006/TEST.properties b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t006/TEST.properties
deleted file mode 100644
index 8b51b2a9115..00000000000
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t006/TEST.properties
+++ /dev/null
@@ -1,24 +0,0 @@
-#
-# Copyright (c) 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.
-#
-# 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.
-#
-
-exclusiveAccess.dirs=.
diff --git a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t006/TestDescription.java b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t006/TestDescription.java
index dacf53b0994..f400b04e543 100644
--- a/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t006/TestDescription.java
+++ b/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/events/EM02/em02t006/TestDescription.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2018, 2020, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2018, 2025, 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
@@ -60,9 +60,12 @@
  *
  * @library /vmTestbase
  *          /test/lib
+ * @build jdk.test.whitebox.WhiteBox
+ * @run driver jdk.test.lib.helpers.ClassFileInstaller jdk.test.whitebox.WhiteBox
  * @run main/othervm/native
  *      -agentlib:em02t006=-waittime=5
  *      -XX:-UseGCOverheadLimit
+ *      -Xbootclasspath/a:. -XX:+UnlockDiagnosticVMOptions -XX:+WhiteBoxAPI
  *      nsk.jvmti.scenarios.events.EM02.em02t006
  */