From 5ec096e7f15b1cb1914ff5abc4cf1ec28302b460 Mon Sep 17 00:00:00 2001
From: Kalin Chan <kalin.chan@payara.fish>
Date: Tue, 24 Sep 2024 14:14:17 +0100
Subject: [PATCH] L2 Cache Deadlock Prevention

---
 .../internal/helper/ConcurrencyManager.java   |  2 +-
 .../internal/sessions/ObjectChangeSet.java    | 50 ++++++++++++-------
 2 files changed, 33 insertions(+), 19 deletions(-)

diff --git a/foundation/org.eclipse.persistence.core/src/main/java/org/eclipse/persistence/internal/helper/ConcurrencyManager.java b/foundation/org.eclipse.persistence.core/src/main/java/org/eclipse/persistence/internal/helper/ConcurrencyManager.java
index 18fdf3f63c0..fd2899e5224 100644
--- a/foundation/org.eclipse.persistence.core/src/main/java/org/eclipse/persistence/internal/helper/ConcurrencyManager.java
+++ b/foundation/org.eclipse.persistence.core/src/main/java/org/eclipse/persistence/internal/helper/ConcurrencyManager.java
@@ -721,7 +721,7 @@ public void releaseDeferredLock() throws ConcurrencyException {
                         throw ConcurrencyException.waitWasInterrupted(interrupted.getMessage());
                     }
                 }
-            } catch (Error error) {
+            } catch (Error | Exception error) {
                 if (!releaseAllLocksAquiredByThreadAlreadyPerformed) {
                     THREADS_WAITING_TO_RELEASE_DEFERRED_LOCKS.remove(currentThread);
                     AbstractSessionLog.getLog().logThrowable(SessionLog.SEVERE, SessionLog.CACHE, error);
diff --git a/foundation/org.eclipse.persistence.core/src/main/java/org/eclipse/persistence/internal/sessions/ObjectChangeSet.java b/foundation/org.eclipse.persistence.core/src/main/java/org/eclipse/persistence/internal/sessions/ObjectChangeSet.java
index bc910625502..434b267a208 100644
--- a/foundation/org.eclipse.persistence.core/src/main/java/org/eclipse/persistence/internal/sessions/ObjectChangeSet.java
+++ b/foundation/org.eclipse.persistence.core/src/main/java/org/eclipse/persistence/internal/sessions/ObjectChangeSet.java
@@ -521,33 +521,47 @@ protected Object getObjectForMerge(MergeManager mergeManager, AbstractSession se
         CacheKey cacheKey = session.getIdentityMapAccessorInstance().getCacheKeyForObject(primaryKey, descriptor.getJavaClass(), descriptor, true);
         if (cacheKey != null) {
             if (cacheKey.acquireReadLockNoWait()) {
-                domainObject = cacheKey.getObject();
-                cacheKey.releaseReadLock();
+                try {
+                    domainObject = cacheKey.getObject();
+                } catch (Exception exception) {
+                    exception.printStackTrace();
+                }
+                finally {
+                    cacheKey.releaseReadLock();
+                }
             } else {
                 if (!mergeManager.isTransitionedToDeferredLocks()) {
                     session.getIdentityMapAccessorInstance().getWriteLockManager().transitionToDeferredLocks(mergeManager);
                 }
                 cacheKey.acquireDeferredLock();
-                domainObject = cacheKey.getObject();
-                int tries = 0;
-                while (domainObject == null) {
-                    ++tries;
-                    if (tries > MAX_TRIES){
-                        session.getParent().log(SessionLog.SEVERE, SessionLog.CACHE, "entity_not_available_during_merge", new Object[]{descriptor.getJavaClassName(), cacheKey.getKey(), Thread.currentThread().getName(), cacheKey.getActiveThread()});
-                        break;
-                    }
-                    synchronized (cacheKey) {
-                        if (cacheKey.isAcquired()) {
-                            try {
-                                cacheKey.wait(10);
-                            } catch (InterruptedException e) {
-                                //ignore and return
+                try {
+                    domainObject = cacheKey.getObject();
+                    int tries = 0;
+                    while (domainObject == null) {
+                        ++tries;
+                        if (tries > MAX_TRIES){
+                            if (session.getParent() != null) {
+                                session.getParent().log(SessionLog.SEVERE, SessionLog.CACHE, "entity_not_available_during_merge", new Object[]{descriptor.getJavaClassName(), cacheKey.getKey(), Thread.currentThread().getName(), cacheKey.getActiveThread()});
                             }
+                            break;
+                        }
+                        synchronized (cacheKey) {
+                            if (cacheKey.isAcquired()) {
+                                try {
+                                    cacheKey.wait(10);
+                                } catch (InterruptedException e) {
+                                    //ignore and return
+                                }
+                            }
+                            domainObject = cacheKey.getObject();
                         }
-                        domainObject = cacheKey.getObject();
                     }
+                } catch (Exception exception) {
+                    exception.printStackTrace();
+                }
+                finally {
+                    cacheKey.releaseDeferredLock();
                 }
-                cacheKey.releaseDeferredLock();
             }
         } else {
             domainObject = mergeManager.registerExistingObjectOfReadOnlyClassInNestedTransaction(getUnitOfWorkClone(), descriptor, session);