A StaleObjectStateException is Thrown When Using a Liferay Service

Issue

After installing Liferay DXP 7.2 Service Pack 1 or Fix Pack 2 a StaleObjectStateException is generated when a customization uses a Liferay service to update or modify data:

  Caused by: org.hibernate.StaleObjectStateException: Row was updated or deleted
  by another transaction (or unsaved-value mapping was incorrect): [com.liferay.portal.model.impl.ContactImpl#8367818]
  at org.hibernate.event.def.DefaultMergeEventListener.entityIsDetached(DefaultMergeEventListener.java:485)
  at org.hibernate.event.def.DefaultMergeEventListener.onMerge(DefaultMergeEventListener.java:255)
  at org.hibernate.event.def.DefaultMergeEventListener.onMerge(DefaultMergeEventListener.java:84)
  at org.hibernate.impl.SessionImpl.fireMerge(SessionImpl.java:867) at org.hibernate.impl.SessionImpl.merge(SessionImpl.java:851)
  at org.hibernate.impl.SessionImpl.merge(SessionImpl.java:855) at com.liferay.portal.dao.orm.hibernate.SessionImpl.merge(SessionImpl.java:241)
  ... 208 more

Resolution

A StaleObjectStateException is commonly thrown by Hibernate when stale data is detected, such as when conflicting modifications are encountered.

General Pattern: if you update a model, but don’t re-capture the return value, future updates to that same model, even within the same thread, may result in a StaleObjectStateException. To resolve this, make sure to store the return value of any methods that update the object:

Incorrect:

_fooLocalService.update(foo);

Correct:

foo = _fooLocalService.update(foo);

Example #1: if you fetch a variable and then update it multiple times within different methods, this may also result in a StaleObjectStateException. This pattern often spans multiple classes (something updated in one class’s instance method is never returned, so another class never knows about the update). To resolve this, make sure that any method that updates a model object also returns that model object:

Incorrect:

public void setLastAccessDate(Foo foo) {
    foo.setLastAccessDate(new Date());
    _fooLocalService.update(foo);
}

public void setLastAccessIPAddress(Foo foo) {
    foo.setLastAccessIPAddress("127.0.0.1");
    _fooLocalService.update(foo);
}

public void service(
    HttpServletRequest request, HttpServletResponse response) {

    Foo foo = _fooLocalService.getFoo(fooId);
    setLastAccessDate(foo);
    setLastAccessIPAddress(foo);
}

Correct:

public Foo setLastAccessDate(Foo foo) {
    foo.setLastAccessDate(new Date());
    return _fooLocalService.update(foo);
}

public Foo setLastAccessIPAddress(Foo foo) {
    foo.setLastAccessIPAddress("127.0.0.1");
    return _fooLocalService.update(foo);
}

public void service(
    HttpServletRequest request, HttpServletResponse response) {

    Foo foo = _fooLocalService.getFoo(fooId);
    foo = setLastAccessDate(foo);
    foo = setLastAccessIPAddress(foo);
}

Example #2: if you fetch a variable and then store it in a shared memory location (such as the HttpSession or an internal cache of frequently accessed objects), this shared memory location may not know about any updates, which may also cause a StaleObjectStateException. To resolve this, you would make sure to reset the value in the shared location any time an update occurs:

Incorrect:

public void setLastAccessDate(Foo foo) {
    foo.setLastAccessDate(new Date());
    _fooLocalService.update(foo);
}

public void service(
    HttpServletRequest request, HttpServletResponse response) {

    Foo foo = _fooLocalService.getFoo(fooId);
    session.setAttribute("FOO", foo);
    setLastAccessDate(foo);
}

Correct:

public Foo setLastAccessDate(Foo foo) {
    foo.setLastAccessDate(new Date());
    return _fooLocalService.update(foo);
}

public void service(
    HttpServletRequest request, HttpServletResponse response) {

    Foo foo = _fooLocalService.getFoo(fooId);
    session.setAttribute("FOO", foo);
    foo = setLastAccessDate(foo);
    session.setAttribute("FOO", foo);
}

Additional Examples from Liferay source: LPS-86385 and LPS-86695

Additional Information

As of Liferay DXP 7.2 Service Pack 1 or Fix Pack 2, additional Liferay services now have MVCC enabled.

Liferay's MVCC implementation relies on Hibernate's optimistic locking system. With this mechanism in place, modifications that Hibernate identifies as conflicting will be revealed.

Below is a list of additional Liferay services that now have MVCC enabled.

Additional Liferay Services with MVCC Enabled

Components	Services	Tables
Account	AccountEntry AccountEntryUserRel	AccountEntry AccountEntryUserRel
Asset	AssetEntryUsage	AssetEntryUsage
Asset Auto Tagger	AssetAutoTaggerEntry	AssetAutoTaggerEntry
Asset Category Property	AssetCategoryProperty	AssetCategoryProperty
Asset Display Page	AssetDisplayPageEntry	AssetDisplayPageEntry
Asset Entry Rel	AssetEntryAssetCategoryRel	AssetEntryAssetCategoryRel
Asset List	AssetListEntry AssetListEntryAssetEntryRel AssetListEntrySegmentsEntryRel AssetListEntryUsage	AssetListEntry AssetListEntryAssetEntryRel AssetListEntrySegmentsEntryRel AssetListEntryUsage
Blogs	BlogsEntry BlogsStatsUser	BlogsEntry BlogsStatsUser
Bookmarks	BookmarksEntry BookmarksFolder	BookmarksEntry BookmarksFolder
Calendar	Calendar CalendarBooking CalendarNotificationTemplate CalendarResource	Calendar CalendarBooking CalendarNotificationTemplate CalendarResource
Document Library Content	DLContent	DLContent
Dynamic Data Mapping	DDMContent DDMDataProviderInstance DDMDataProviderInstanceLink DDMFormInstance DDMFormInstanceRecord DDMFormInstanceRecordVersion DDMFormInstanceVersion DDMStorageLink DDMStructure DDMStructureLayout DDMStructureLink DDMStructureVersion DDMTemplate DDMTemplateLink DDMTemplateVersion	DDMContent DDMDataProviderInstance DDMDataProviderInstanceLink DDMFormInstance DDMFormInstanceRecord DDMFormInstanceRecordVersion DDMFormInstanceVersion DDMStorageLink DDMStructure DDMStructureLayout DDMStructureLink DDMStructureVersion DDMTemplate DDMTemplateLink DDMTemplateVersion
Fragment	FragmentCollection FragmentEntry FragmentEntryLink	FragmentCollection FragmentEntry FragmentEntryLink
Journal	JournalArticle JournalArticleLocalization JournalArticleResource JournalContentSearch JournalFeed JournalFolder	JournalArticle JournalArticleLocalization JournalArticleResource JournalContentSearch JournalFeed JournalFolder
Knowledge Base	KBArticle KBComment KBFolder KBTemplate	KBArticle KBComment KBFolder KBTemplate
Layout Page Template	LayoutPageTemplateCollection LayoutPageTemplateEntry LayoutPageTemplateStructure LayoutPageTemplateStructureRel	LayoutPageTemplateCollection LayoutPageTemplateEntry LayoutPageTemplateStructure LayoutPageTemplateStructureRel
Mobile Device Rules	MDRAction MDRRule MDRRuleGroup MDRRuleGroupInstance	MDRAction MDRRule MDRRuleGroup MDRRuleGroupInstance
Segments	SegmentsEntry SegmentsEntryRel SegmentsExperience SegmentsExperiment SegmentsExperimentRel	SegmentsEntry SegmentsEntryRel SegmentsExperience SegmentsExperiment SegmentsExperimentRel
Site	SiteFriendlyURL	SiteFriendlyURL
Site Navigation	SiteNavigationMenu SiteNavigationMenuItem	SiteNavigationMenu SiteNavigationMenuItem
Trash	TrashEntry TrashVersion	TrashEntry TrashVersion
Wiki	WikiNode WikiPage WikiPageResource	WikiNode WikiPage WikiPageResource