Make UseCompactObjectHeaders the default and adjust CDS archives.

make/Images.gmk

@@ -143,11 +143,10 @@ define CreateCDSArchive
   $1_$2_COOPS_OPTION := $(if $(findstring _nocoops, $2),-XX:-UseCompressedOops)
   # enable and also explicitly disable coh as needed.
   ifeq ($(call isTargetCpuBits, 64), true)
-    $1_$2_COH_OPTION := -XX:+UnlockExperimentalVMOptions \
-                        $(if $(findstring _coh, $2),-XX:+UseCompactObjectHeaders,-XX:-UseCompactObjectHeaders)
+    $1_$2_COH_OPTION := $(if $(findstring _nocoh, $2),-XX:-UseCompactObjectHeaders,-XX:+UseCompactObjectHeaders)
   endif
   $1_$2_$3_DUMP_EXTRA_ARG := $$($1_$2_COOPS_OPTION) $$($1_$2_COH_OPTION) $(if $(findstring _preview, $3), --enable-preview,)
-  $1_$2_$3_DUMP_TYPE      := $(if $(findstring _nocoops, $2),-NOCOOPS,)$(if $(findstring _coh, $2),-COH,)$(if $(findstring _preview, $3),-PREVIEW,)
+  $1_$2_$3_DUMP_TYPE      := $(if $(findstring _nocoops, $2),-NOCOOPS,)$(if $(findstring _nocoh, $2),-NOCOH,)$(if $(findstring _preview, $3),-PREVIEW,)
 
   $1_$2_$3_CDS_DUMP_FLAGS := $(CDS_DUMP_FLAGS) $(if $(filter g1gc, $(JVM_FEATURES_$1)), -XX:+UseG1GC)
 
@@ -205,12 +204,12 @@ ifeq ($(BUILD_CDS_ARCHIVE), true)
     )
     ifeq ($(BUILD_CDS_ARCHIVE_COH), true)
       $(foreach v, $(JVM_VARIANTS), \
-        $(eval $(call CreateCDSArchive,$v,_coh)) \
-        $(eval $(call CreateCDSArchive,$v,_coh,_preview)) \
+        $(eval $(call CreateCDSArchive,$v,_nocoh)) \
+        $(eval $(call CreateCDSArchive,$v,_nocoh,_preview)) \
       )
       $(foreach v, $(JVM_VARIANTS), \
-        $(eval $(call CreateCDSArchive,$v,_nocoops_coh)) \
-        $(eval $(call CreateCDSArchive,$v,_nocoops_coh,_preview)) \
+        $(eval $(call CreateCDSArchive,$v,_nocoops_nocoh)) \
+        $(eval $(call CreateCDSArchive,$v,_nocoops_nocoh,_preview)) \
       )
     endif
   endif

make/RunTests.gmk

@@ -972,11 +972,6 @@ define SetupRunJtregTestBody
     JTREG_AUTO_PROBLEM_LISTS += ProblemList-enable-preview.txt
   endif
 
-  ifneq ($$(findstring -XX:+UseCompactObjectHeaders, $$(JTREG_ALL_OPTIONS)), )
-    JTREG_AUTO_PROBLEM_LISTS += ProblemList-coh.txt
-  endif
-
-
   ifneq ($$(JTREG_EXTRA_PROBLEM_LISTS), )
     # Accept both absolute paths as well as relative to the current test root.
     $1_JTREG_BASIC_OPTIONS += $$(addprefix $$(JTREG_PROBLEM_LIST_PREFIX), $$(wildcard \

src/hotspot/share/cds/cdsConfig.cpp

@@ -138,10 +138,10 @@ const char* CDSConfig::default_archive_path() {
     if (!UseCompressedOops) {
       tmp.print_raw("_nocoops");
     }
-    if (UseCompactObjectHeaders) {
+    if (!UseCompactObjectHeaders) {
       // Note that generation of xxx_coh.jsa variants require
       // --enable-cds-archive-coh at build time
-      tmp.print_raw("_coh");
+      tmp.print_raw("_nocoh");
     }
 #endif
     if (Arguments::is_valhalla_enabled()) {

src/hotspot/share/runtime/globals.hpp

@@ -124,7 +124,7 @@ const size_t minimumSymbolTableSize = 1024;
           "Use 32-bit object references in 64-bit VM. "                     \
           "lp64_product means flag is always constant in 32 bit VM")        \
                                                                             \
-  product(bool, UseCompactObjectHeaders, false,                             \
+  product(bool, UseCompactObjectHeaders, true,                              \
           "Use compact 64-bit object headers in 64-bit VM")                 \
                                                                             \
   product(int, ObjectAlignmentInBytes, 8,                                   \

test/hotspot/jtreg/runtime/cds/TestDefaultArchiveLoading.java

@@ -120,7 +120,7 @@ public static void main(String[] args) throws Exception {
         switch (args[0]) {
             case "nocoops_nocoh":
                 coh = coops = '-';
-                archiveSuffix = "_nocoops";
+                archiveSuffix = "_nocoops_nocoh";
                 if (!isArchiveAvailable(coops, coh, archiveSuffix)) {
                     throw new SkippedException("Skipping test due to " +
                                                archivePath(archiveSuffix).toString() + " not available");
@@ -129,7 +129,7 @@ public static void main(String[] args) throws Exception {
             case "nocoops_coh":
                 coops = '-';
                 coh = '+';
-                archiveSuffix = "_nocoops_coh";
+                archiveSuffix = "_nocoops";
                 if (!isArchiveAvailable(coops, coh, archiveSuffix)) {
                     throw new SkippedException("Skipping test due to " +
                                                archivePath(archiveSuffix).toString() + " not available");
@@ -138,15 +138,15 @@ public static void main(String[] args) throws Exception {
             case "coops_nocoh":
                 coops = '+';
                 coh = '-';
-                archiveSuffix = "";
+                archiveSuffix = "_nocoh";
                 if (!isArchiveAvailable(coops, coh, archiveSuffix)) {
                     throw new SkippedException("Skipping test due to " +
                                                archivePath(archiveSuffix).toString() + " not available");
                 }
                 break;
             case "coops_coh":
                 coh = coops = '+';
-                archiveSuffix = "_coh";
+                archiveSuffix = "";
                 if (!isArchiveAvailable(coops, coh, archiveSuffix)) {
                     throw new SkippedException("Skipping test due to " +
                                                archivePath(archiveSuffix).toString() + " not available");

test/jdk/ProblemList-coh.txt

@@ -1,44 +1,3 @@
-#
-# Copyright (c) 2026, 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.
-#
-
-#############################################################################
-#
-# List of quarantined tests for testing with -XX:+UseCompactObjectHeaders
-#
-#############################################################################
-
-#############################################################################
-
-# Preview project specific failures go here at the end of the file.
-#
-# These are NOT failures that occur with the '--enable-preview' option
-# specified; those go in the appropriate ProblemList-enable-preview.txt file.
-# These are failures that occur WITHOUT the '--enable-preview' option
-# specified AND occur because of some issue with preview project code,
-# in either implementation or test code.
-
-#############################################################################
-
 # Valhalla failures start here:
 
 # The following test failures DID NOT reproduce during Tier[1-8] testing 

test/jdk/tools/jlink/plugins/CDSPluginTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021, 2024, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2021, 2026, 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
@@ -77,15 +77,11 @@ public static void main(String[] args) throws Throwable {
         subDir += "server" + sep;
 
         WhiteBox wb = WhiteBox.getWhiteBox();
-        boolean COMPACT_HEADERS = Platform.is64bit() &&
-                                  wb.getBooleanVMFlag("UseCompactObjectHeaders") &&
-                                  wb.isDefaultVMFlag("UseCompactObjectHeaders");
-
-        String suffix = COMPACT_HEADERS ? "_coh.jsa" : ".jsa";
+        String suffix = ".jsa";
 
         if (Platform.isAArch64() || Platform.isX64()) {
             helper.checkImage(image, module, null, null,
-                      new String[] { subDir + "classes" + suffix, subDir + "classes_nocoops" + suffix });
+                      new String[] { subDir + "classes" + suffix, subDir + "classes_nocoops" + suffix});
         } else {
             helper.checkImage(image, module, null, null,
                       new String[] { subDir + "classes" + suffix });