How many JFactory & application issues are in this guide?

This guide covers 32 catalog entries with before/after replacements.

Joomla JFactory & application changes: Joomla 3 → 4, 5 and 6

32 issues in this guide

JFactory and the old application stack dominate Joomla 3 to 6 fatals. This guide groups 32 entries covering $app->isAdmin(), $app->redirect($url, $msg, 'error'), plg_behaviour_compat, plg_behaviour_compat6, JApplicationHelper::parseXMLLangMetaFile(), JApplicationAdministrator, JApplicationBase, JApplicationCms, JApplicationHelper, JApplicationSite, and 22 more. The general replacement is Factory::getApplication() or the DI container, then application services (getIdentity, getSession, getLanguage, getDocument, getConfig) instead of static JFactory calls. Client checks move to isClient('administrator') / isClient('site'); redirect messages enqueue first, then redirect($url). Behaviour – Backward Compatibility and Behaviour – Backward Compatibility 6 are documented so you know which plugin covers J* aliases. Hop mix: 8 at Joomla 3 → 4; 24 at Joomla 5 → 6. On Joomla 4 many names still resolve via aliases; native Joomla 6 does not. Disable the BC plugin on a Joomla 5 staging site and match every Class "J…" not found against the anchors below. Catalog replacements in this guide include $app->isAdmin() → $app->isClient('administrator') / isClient('site'); $app->redirect($url, $msg, 'error') → enqueueMessage then redirect($url); plg_behaviour_compat → Rewrite J* classes so BC5 can stay off, then upgrade to Joomla 6; plg_behaviour_compat6 → Does not restore JFactory / JRequest / MooTools. Open each h2 anchor for the full before/after, fix list, and error strings shipped in the reference data.

APP-ISADMIN-001

$app->isAdmin()

isAdmin() / isSite()

Joomla 4 can have more application clients than site/admin. isAdmin and isSite were removed. isClient() is the replacement.

$app->isAdmin() → $app->isClient('administrator') / isClient('site')

Dies at Joomla 3 → 4

Dies at Joomla 3 → 4J3: Works nativelyJ4: Removed — fatalJ6: Removed — fatalBC plugin: no — already dead on J4Mechanical renameJoomla API

What you will see

Call to undefined method ...::isAdmin()
Call to undefined method ...::isSite()

Symptoms people search

admin-only code runs on the site · undefined method isAdmin

Replace this code

Swap $app->isAdmin() for $app->isClient('administrator') / isClient('site').

Joomla 3

Remove or stop calling this

if ($app->isAdmin()) { ... }
if ($app->isSite()) { ... }

Joomla 4 / 6

Use this instead

if ($app->isClient('administrator')) { ... }
if ($app->isClient('site')) { ... }

How to fix it

1Replace isAdmin() with isClient('administrator').
2Replace isSite() with isClient('site').

Also known as

isAdmin · isSite · isClient

Scan a ZIP for this Ask Infyways to fix it

APP-REDIRECT-MSG-001

$app->redirect($url, $msg, 'error')

redirect($url, $msg, $type) old signature

Joomla 4 redirect no longer takes message + type. Passing them fatals or ignores.

$app->redirect($url, $msg, 'error') → enqueueMessage then redirect($url)

Dies at Joomla 3 → 4

Dies at Joomla 3 → 4J3: Works nativelyJ4: Removed — fatalJ6: Removed — fatalBC plugin: no — already dead on J4Patch possible — review itJoomla API

What you will see

Too many arguments to function ...::redirect

Symptoms people search

redirect 500 after save

Replace this code

Swap $app->redirect($url, $msg, 'error') for enqueueMessage then redirect($url).

Joomla 3

Remove or stop calling this

$app->redirect('index.php?option=com_lms', 'Saved', 'message');

Joomla 4 / 6

Use this instead

$app->enqueueMessage('Saved');
$app->redirect('index.php?option=com_lms');

How to fix it

1enqueueMessage first.
2redirect with URL (and optional HTTP code) only.

Also known as

redirect message type

Scan a ZIP for this Ask Infyways to fix it

BC5-DISABLE-TEST-001

plg_behaviour_compat

Site dies when you disable Behaviour – Backward Compatibility

There are two plugins. Behaviour – Backward Compatibility (no number) restores JFactory, JText, JHtml, and hundreds of J* names on Joomla 5. You MUST disable it before Joomla 6. Behaviour – Backward Compatibility 6 is a different plugin and does not restore JRequest or JFactory. If disabling the first plugin whitescreens the site, you are not Joomla 6 ready.

plg_behaviour_compat → Rewrite J* classes so BC5 can stay off, then upgrade to Joomla 6

Dies at Joomla 5 → 6

Dies at Joomla 5 → 6J3: Works nativelyJ4: Alias (old name still resolves)J6: Removed — fatalBC plugin: covers the class nameYou rewrite thisJoomla API

What you will see

Class "JFactory" not found
Class "JText" not found
Class "JHtml" not found

Symptoms people search

white screen after disabling compatibility plugin · cannot upgrade to Joomla 6 · plugin required for site to load · backward compatibility

Replace this code

Swap plg_behaviour_compat for Rewrite J* classes so BC5 can stay off, then upgrade to Joomla 6.

Joomla 3

Remove or stop calling this

// Joomla 5 with plugin enabled — site “works”
$app = JFactory::getApplication();

Joomla 4 / 6

Use this instead

use Joomla\CMS\Factory;
$app = Factory::getApplication();
// Then disable the plugin on staging. It must stay off to upgrade to Joomla 6.

How to fix it

1On Joomla 5.4 staging: System → Plugins → disable Behaviour – Backward Compatibility (no number).
2Note every Class "J…" not found error. Those are this reference.
3Fix them, then retry. Only then run the Joomla 6 update.
4Do not confuse it with Backward Compatibility 6 — that one does not bring J* names back.

Also known as

Behaviour - Backward Compatibility · plg_behaviour_compat · BC plugin · compat plugin · Backward Compatibility 6

Scan a ZIP for this Ask Infyways to fix it

BC6-PLUGIN-001

plg_behaviour_compat6

Behaviour – Backward Compatibility 6 (the other plugin)

Two plugins, two jobs. Searching “compatibility plugin” must explain both or people enable the wrong one.

plg_behaviour_compat6 → Does not restore JFactory / JRequest / MooTools

Dies at Joomla 5 → 6

Dies at Joomla 5 → 6J3: Works nativelyJ4: Works nativelyJ6: Changed behaviourBC plugin: not applicableArchitecture change — no auto-fixJoomla API

Symptoms people search

backward compatibility 6 · compat6 · two compatibility plugins

Replace this code

Swap plg_behaviour_compat6 for Does not restore JFactory / JRequest / MooTools.

Joomla 3

Remove or stop calling this

// Confusing this with Behaviour – Backward Compatibility (no number)

Joomla 4 / 6

Use this instead

BC6 helps some Joomla 5→6 namespaced class moves. It will not load J* globals. Disable BC5 before Joomla 6; BC6 is a different plugin.

How to fix it

1BC5 (no number): J* aliases on Joomla 5. Must be OFF to go to 6.
2BC6: selected J5→J6 class moves. Enabled on 5.4; disabled on new J6 installs.

Also known as

plg_behaviour_compat6 · Backward Compatibility 6 · BC6

Scan a ZIP for this Ask Infyways to fix it

JAPPHELPER-PARSEXML-001

JApplicationHelper::parseXMLLangMetaFile()

JApplicationHelper::parseXMLLangMetaFile

That helper was deleted in Joomla 4.

JApplicationHelper::parseXMLLangMetaFile() → No replacement — use langmetadata.xml APIs

Dies at Joomla 3 → 4

Dies at Joomla 3 → 4J3: Works nativelyJ4: Removed — fatalJ6: Removed — fatalBC plugin: no — already dead on J4Architecture change — no auto-fixJoomla API

What you will see

Call to undefined method ...::parseXMLLangMetaFile

Symptoms people search

language pack install helper fatal

Replace this code

Swap JApplicationHelper::parseXMLLangMetaFile() for No replacement — use langmetadata.xml APIs.

Joomla 3

Remove or stop calling this

JApplicationHelper::parseXMLLangMetaFile($path);

Joomla 4 / 6

Use this instead

Read language metadata through LanguageHelper / langmetadata.xml. Do not call parseXMLLangMetaFile.

How to fix it

1Stop calling it.
2Parse langmetadata.xml if you need metadata.

Also known as

parseXMLLangMetaFile

There is no 1:1 swap for this one. The architecture changed. If you cannot rewrite it, Infyways can.

Scan a ZIP for this Ask Infyways to fix it

JAPPLICATIONADMIN-CLASS-001

JApplicationAdministrator

JApplicationAdministrator class name

JApplicationAdministrator is a Joomla 3 global class. Joomla 4 still has an alias. Joomla 5 needs the Behaviour – Backward Compatibility plugin. Native Joomla 6 does not load that alias — you get Class "JApplicationAdministrator" not found.

JApplicationAdministrator → Joomla\CMS\Application\AdministratorApplication

Dies at Joomla 5 → 6

Dies at Joomla 5 → 6J3: Works nativelyJ4: Alias (old name still resolves)J6: Removed — fatalBC plugin: covers the class nameMechanical renameJoomla API

What you will see

Class "JApplicationAdministrator" not found
Class 'JApplicationAdministrator' not found
Failed to open stream: JApplicationAdministrator

Symptoms people search

white screen after disabling compatibility plugin · class not found on Joomla 6 · works on Joomla 5 until I turn off backward compatibility

Replace this code

Swap JApplicationAdministrator for Joomla\CMS\Application\AdministratorApplication.

Joomla 3

Remove or stop calling this

JApplicationAdministrator::getInstance();
// or new JApplicationAdministrator()

Joomla 4 / 6

Use this instead

use Joomla\CMS\Application\AdministratorApplication;

// Call the namespaced class. Do not keep the J prefix.

How to fix it

1Add a use statement for Joomla\CMS\Application\AdministratorApplication.
2Replace every JApplicationAdministrator with the short class name from that use line.
3Disable Behaviour – Backward Compatibility on a Joomla 5 staging site. If it fatals, this class is still in the code.

Also known as

JApplicationAdministrator · Joomla\CMS\Application\AdministratorApplication · class alias · J prefix

Scan a ZIP for this Ask Infyways to fix it

JAPPLICATIONBASE-CLASS-001

JApplicationBase

JApplicationBase class name

JApplicationBase is a Joomla 3 global class. Joomla 4 still has an alias. Joomla 5 needs the Behaviour – Backward Compatibility plugin. Native Joomla 6 does not load that alias — you get Class "JApplicationBase" not found.

JApplicationBase → Joomla\CMS\Application\BaseApplication

Dies at Joomla 5 → 6

Dies at Joomla 5 → 6J3: Works nativelyJ4: Alias (old name still resolves)J6: Removed — fatalBC plugin: covers the class nameMechanical renameJoomla API

What you will see

Class "JApplicationBase" not found
Class 'JApplicationBase' not found
Failed to open stream: JApplicationBase

Symptoms people search

white screen after disabling compatibility plugin · class not found on Joomla 6 · works on Joomla 5 until I turn off backward compatibility

Replace this code

Swap JApplicationBase for Joomla\CMS\Application\BaseApplication.

Joomla 3

Remove or stop calling this

JApplicationBase::getInstance();
// or new JApplicationBase()

Joomla 4 / 6

Use this instead

use Joomla\CMS\Application\BaseApplication;

// Call the namespaced class. Do not keep the J prefix.

How to fix it

1Add a use statement for Joomla\CMS\Application\BaseApplication.
2Replace every JApplicationBase with the short class name from that use line.
3Disable Behaviour – Backward Compatibility on a Joomla 5 staging site. If it fatals, this class is still in the code.

Also known as

JApplicationBase · Joomla\CMS\Application\BaseApplication · class alias · J prefix

Scan a ZIP for this Ask Infyways to fix it

JAPPLICATIONCMS-CLASS-001

JApplicationCms

JApplicationCms class name

JApplicationCms is a Joomla 3 global class. Joomla 4 still has an alias. Joomla 5 needs the Behaviour – Backward Compatibility plugin. Native Joomla 6 does not load that alias — you get Class "JApplicationCms" not found.

JApplicationCms → Joomla\CMS\Application\CMSApplication

Dies at Joomla 5 → 6

Dies at Joomla 5 → 6J3: Works nativelyJ4: Alias (old name still resolves)J6: Removed — fatalBC plugin: covers the class nameMechanical renameJoomla API

What you will see

Class "JApplicationCms" not found
Class 'JApplicationCms' not found
Failed to open stream: JApplicationCms

Symptoms people search

white screen after disabling compatibility plugin · class not found on Joomla 6 · works on Joomla 5 until I turn off backward compatibility

Replace this code

Swap JApplicationCms for Joomla\CMS\Application\CMSApplication.

Joomla 3

Remove or stop calling this

JApplicationCms::getInstance();
// or new JApplicationCms()

Joomla 4 / 6

Use this instead

use Joomla\CMS\Application\CMSApplication;

// Call the namespaced class. Do not keep the J prefix.

How to fix it

1Add a use statement for Joomla\CMS\Application\CMSApplication.
2Replace every JApplicationCms with the short class name from that use line.
3Disable Behaviour – Backward Compatibility on a Joomla 5 staging site. If it fatals, this class is still in the code.

Also known as

JApplicationCms · Joomla\CMS\Application\CMSApplication · class alias · J prefix

Scan a ZIP for this Ask Infyways to fix it

JAPPLICATIONHELPER-CLASS-001

JApplicationHelper

JApplicationHelper class name

JApplicationHelper is a Joomla 3 global class. Joomla 4 still has an alias. Joomla 5 needs the Behaviour – Backward Compatibility plugin. Native Joomla 6 does not load that alias — you get Class "JApplicationHelper" not found.

JApplicationHelper → Joomla\CMS\Application\ApplicationHelper

Dies at Joomla 5 → 6

Dies at Joomla 5 → 6J3: Works nativelyJ4: Alias (old name still resolves)J6: Removed — fatalBC plugin: covers the class nameMechanical renameJoomla API

What you will see

Class "JApplicationHelper" not found
Class 'JApplicationHelper' not found
Failed to open stream: JApplicationHelper

Symptoms people search

white screen after disabling compatibility plugin · class not found on Joomla 6 · works on Joomla 5 until I turn off backward compatibility

Replace this code

Swap JApplicationHelper for Joomla\CMS\Application\ApplicationHelper.

Joomla 3

Remove or stop calling this

JApplicationHelper::getInstance();
// or new JApplicationHelper()

Joomla 4 / 6

Use this instead

use Joomla\CMS\Application\ApplicationHelper;

// Call the namespaced class. Do not keep the J prefix.

How to fix it

1Add a use statement for Joomla\CMS\Application\ApplicationHelper.
2Replace every JApplicationHelper with the short class name from that use line.
3Disable Behaviour – Backward Compatibility on a Joomla 5 staging site. If it fatals, this class is still in the code.

Also known as

JApplicationHelper · Joomla\CMS\Application\ApplicationHelper · class alias · J prefix

Scan a ZIP for this Ask Infyways to fix it

JAPPLICATIONSITE-CLASS-001

JApplicationSite

JApplicationSite class name

JApplicationSite is a Joomla 3 global class. Joomla 4 still has an alias. Joomla 5 needs the Behaviour – Backward Compatibility plugin. Native Joomla 6 does not load that alias — you get Class "JApplicationSite" not found.

JApplicationSite → Joomla\CMS\Application\SiteApplication

Dies at Joomla 5 → 6

Dies at Joomla 5 → 6J3: Works nativelyJ4: Alias (old name still resolves)J6: Removed — fatalBC plugin: covers the class nameMechanical renameJoomla API

What you will see

Class "JApplicationSite" not found
Class 'JApplicationSite' not found
Failed to open stream: JApplicationSite

Symptoms people search

white screen after disabling compatibility plugin · class not found on Joomla 6 · works on Joomla 5 until I turn off backward compatibility

Replace this code

Swap JApplicationSite for Joomla\CMS\Application\SiteApplication.

Joomla 3

Remove or stop calling this

JApplicationSite::getInstance();
// or new JApplicationSite()

Joomla 4 / 6

Use this instead

use Joomla\CMS\Application\SiteApplication;

// Call the namespaced class. Do not keep the J prefix.

How to fix it

1Add a use statement for Joomla\CMS\Application\SiteApplication.
2Replace every JApplicationSite with the short class name from that use line.
3Disable Behaviour – Backward Compatibility on a Joomla 5 staging site. If it fatals, this class is still in the code.

Also known as

JApplicationSite · Joomla\CMS\Application\SiteApplication · class alias · J prefix

Scan a ZIP for this Ask Infyways to fix it

JAPPLICATIONWEB-CLASS-001

JApplicationWeb

JApplicationWeb class name

JApplicationWeb is a Joomla 3 global class. Joomla 4 still has an alias. Joomla 5 needs the Behaviour – Backward Compatibility plugin. Native Joomla 6 does not load that alias — you get Class "JApplicationWeb" not found.

JApplicationWeb → Joomla\CMS\Application\WebApplication

Dies at Joomla 5 → 6

Dies at Joomla 5 → 6J3: Works nativelyJ4: Alias (old name still resolves)J6: Removed — fatalBC plugin: covers the class nameMechanical renameJoomla API

What you will see

Class "JApplicationWeb" not found
Class 'JApplicationWeb' not found
Failed to open stream: JApplicationWeb

Symptoms people search

white screen after disabling compatibility plugin · class not found on Joomla 6 · works on Joomla 5 until I turn off backward compatibility

Replace this code

Swap JApplicationWeb for Joomla\CMS\Application\WebApplication.

Joomla 3

Remove or stop calling this

JApplicationWeb::getInstance();
// or new JApplicationWeb()

Joomla 4 / 6

Use this instead

use Joomla\CMS\Application\WebApplication;

// Call the namespaced class. Do not keep the J prefix.

How to fix it

1Add a use statement for Joomla\CMS\Application\WebApplication.
2Replace every JApplicationWeb with the short class name from that use line.
3Disable Behaviour – Backward Compatibility on a Joomla 5 staging site. If it fatals, this class is still in the code.

Also known as

JApplicationWeb · Joomla\CMS\Application\WebApplication · class alias · J prefix

Scan a ZIP for this Ask Infyways to fix it

JDOCUMENT-CLASS-001

JDocument

JDocument class name

JDocument is a Joomla 3 global class. Joomla 4 still has an alias. Joomla 5 needs the Behaviour – Backward Compatibility plugin. Native Joomla 6 does not load that alias — you get Class "JDocument" not found.

JDocument → Joomla\CMS\Document\Document

Dies at Joomla 5 → 6

Dies at Joomla 5 → 6J3: Works nativelyJ4: Alias (old name still resolves)J6: Removed — fatalBC plugin: covers the class nameMechanical renameJoomla API

What you will see

Class "JDocument" not found
Class 'JDocument' not found
Failed to open stream: JDocument

Symptoms people search

white screen after disabling compatibility plugin · class not found on Joomla 6 · works on Joomla 5 until I turn off backward compatibility

Replace this code

Swap JDocument for Joomla\CMS\Document\Document.

Joomla 3

Remove or stop calling this

JDocument::getInstance();
// or new JDocument()

Joomla 4 / 6

Use this instead

use Joomla\CMS\Document\Document;

// Call the namespaced class. Do not keep the J prefix.

How to fix it

1Add a use statement for Joomla\CMS\Document\Document.
2Replace every JDocument with the short class name from that use line.
3Disable Behaviour – Backward Compatibility on a Joomla 5 staging site. If it fatals, this class is still in the code.

Also known as

JDocument · Joomla\CMS\Document\Document · class alias · J prefix

Scan a ZIP for this Ask Infyways to fix it

JDOCUMENTERROR-CLASS-001

JDocumentError

JDocumentError class name

JDocumentError is a Joomla 3 global class. Joomla 4 still has an alias. Joomla 5 needs the Behaviour – Backward Compatibility plugin. Native Joomla 6 does not load that alias — you get Class "JDocumentError" not found.

JDocumentError → Joomla\CMS\Document\ErrorDocument

Dies at Joomla 5 → 6

Dies at Joomla 5 → 6J3: Works nativelyJ4: Alias (old name still resolves)J6: Removed — fatalBC plugin: covers the class nameMechanical renameJoomla API

What you will see

Class "JDocumentError" not found
Class 'JDocumentError' not found
Failed to open stream: JDocumentError

Symptoms people search

white screen after disabling compatibility plugin · class not found on Joomla 6 · works on Joomla 5 until I turn off backward compatibility

Replace this code

Swap JDocumentError for Joomla\CMS\Document\ErrorDocument.

Joomla 3

Remove or stop calling this

JDocumentError::getInstance();
// or new JDocumentError()

Joomla 4 / 6

Use this instead

use Joomla\CMS\Document\ErrorDocument;

// Call the namespaced class. Do not keep the J prefix.

How to fix it

1Add a use statement for Joomla\CMS\Document\ErrorDocument.
2Replace every JDocumentError with the short class name from that use line.
3Disable Behaviour – Backward Compatibility on a Joomla 5 staging site. If it fatals, this class is still in the code.

Also known as

JDocumentError · Joomla\CMS\Document\ErrorDocument · class alias · J prefix

Scan a ZIP for this Ask Infyways to fix it

JDOCUMENTFEED-CLASS-001

JDocumentFeed

JDocumentFeed class name

JDocumentFeed is a Joomla 3 global class. Joomla 4 still has an alias. Joomla 5 needs the Behaviour – Backward Compatibility plugin. Native Joomla 6 does not load that alias — you get Class "JDocumentFeed" not found.

JDocumentFeed → Joomla\CMS\Document\FeedDocument

Dies at Joomla 5 → 6

Dies at Joomla 5 → 6J3: Works nativelyJ4: Alias (old name still resolves)J6: Removed — fatalBC plugin: covers the class nameMechanical renameJoomla API

What you will see

Class "JDocumentFeed" not found
Class 'JDocumentFeed' not found
Failed to open stream: JDocumentFeed

Symptoms people search

white screen after disabling compatibility plugin · class not found on Joomla 6 · works on Joomla 5 until I turn off backward compatibility

Replace this code

Swap JDocumentFeed for Joomla\CMS\Document\FeedDocument.

Joomla 3

Remove or stop calling this

JDocumentFeed::getInstance();
// or new JDocumentFeed()

Joomla 4 / 6

Use this instead

use Joomla\CMS\Document\FeedDocument;

// Call the namespaced class. Do not keep the J prefix.

How to fix it

1Add a use statement for Joomla\CMS\Document\FeedDocument.
2Replace every JDocumentFeed with the short class name from that use line.
3Disable Behaviour – Backward Compatibility on a Joomla 5 staging site. If it fatals, this class is still in the code.

Also known as

JDocumentFeed · Joomla\CMS\Document\FeedDocument · class alias · J prefix

Scan a ZIP for this Ask Infyways to fix it

JDOCUMENTHTML-CLASS-001

JDocumentHtml

JDocumentHtml class name

JDocumentHtml is a Joomla 3 global class. Joomla 4 still has an alias. Joomla 5 needs the Behaviour – Backward Compatibility plugin. Native Joomla 6 does not load that alias — you get Class "JDocumentHtml" not found.

JDocumentHtml → Joomla\CMS\Document\HtmlDocument

Dies at Joomla 5 → 6

Dies at Joomla 5 → 6J3: Works nativelyJ4: Alias (old name still resolves)J6: Removed — fatalBC plugin: covers the class nameMechanical renameJoomla API

What you will see

Class "JDocumentHtml" not found
Class 'JDocumentHtml' not found
Failed to open stream: JDocumentHtml

Symptoms people search

white screen after disabling compatibility plugin · class not found on Joomla 6 · works on Joomla 5 until I turn off backward compatibility

Replace this code

Swap JDocumentHtml for Joomla\CMS\Document\HtmlDocument.

Joomla 3

Remove or stop calling this

JDocumentHtml::getInstance();
// or new JDocumentHtml()

Joomla 4 / 6

Use this instead

use Joomla\CMS\Document\HtmlDocument;

// Call the namespaced class. Do not keep the J prefix.

How to fix it

1Add a use statement for Joomla\CMS\Document\HtmlDocument.
2Replace every JDocumentHtml with the short class name from that use line.
3Disable Behaviour – Backward Compatibility on a Joomla 5 staging site. If it fatals, this class is still in the code.

Also known as

JDocumentHtml · Joomla\CMS\Document\HtmlDocument · class alias · J prefix

Scan a ZIP for this Ask Infyways to fix it

JDOCUMENTJSON-CLASS-001

JDocumentJson

JDocumentJson class name

JDocumentJson is a Joomla 3 global class. Joomla 4 still has an alias. Joomla 5 needs the Behaviour – Backward Compatibility plugin. Native Joomla 6 does not load that alias — you get Class "JDocumentJson" not found.

JDocumentJson → Joomla\CMS\Document\JsonDocument

Dies at Joomla 5 → 6

Dies at Joomla 5 → 6J3: Works nativelyJ4: Alias (old name still resolves)J6: Removed — fatalBC plugin: covers the class nameMechanical renameJoomla API

What you will see

Class "JDocumentJson" not found
Class 'JDocumentJson' not found
Failed to open stream: JDocumentJson

Symptoms people search

white screen after disabling compatibility plugin · class not found on Joomla 6 · works on Joomla 5 until I turn off backward compatibility

Replace this code

Swap JDocumentJson for Joomla\CMS\Document\JsonDocument.

Joomla 3

Remove or stop calling this

JDocumentJson::getInstance();
// or new JDocumentJson()

Joomla 4 / 6

Use this instead

use Joomla\CMS\Document\JsonDocument;

// Call the namespaced class. Do not keep the J prefix.

How to fix it

1Add a use statement for Joomla\CMS\Document\JsonDocument.
2Replace every JDocumentJson with the short class name from that use line.
3Disable Behaviour – Backward Compatibility on a Joomla 5 staging site. If it fatals, this class is still in the code.

Also known as

JDocumentJson · Joomla\CMS\Document\JsonDocument · class alias · J prefix · JDocumentJSON

Scan a ZIP for this Ask Infyways to fix it

JDOCUMENTRAW-CLASS-001

JDocumentRaw

JDocumentRaw class name

JDocumentRaw is a Joomla 3 global class. Joomla 4 still has an alias. Joomla 5 needs the Behaviour – Backward Compatibility plugin. Native Joomla 6 does not load that alias — you get Class "JDocumentRaw" not found.

JDocumentRaw → Joomla\CMS\Document\RawDocument

Dies at Joomla 5 → 6

Dies at Joomla 5 → 6J3: Works nativelyJ4: Alias (old name still resolves)J6: Removed — fatalBC plugin: covers the class nameMechanical renameJoomla API

What you will see

Class "JDocumentRaw" not found
Class 'JDocumentRaw' not found
Failed to open stream: JDocumentRaw

Symptoms people search

white screen after disabling compatibility plugin · class not found on Joomla 6 · works on Joomla 5 until I turn off backward compatibility

Replace this code

Swap JDocumentRaw for Joomla\CMS\Document\RawDocument.

Joomla 3

Remove or stop calling this

JDocumentRaw::getInstance();
// or new JDocumentRaw()

Joomla 4 / 6

Use this instead

use Joomla\CMS\Document\RawDocument;

// Call the namespaced class. Do not keep the J prefix.

How to fix it

1Add a use statement for Joomla\CMS\Document\RawDocument.
2Replace every JDocumentRaw with the short class name from that use line.
3Disable Behaviour – Backward Compatibility on a Joomla 5 staging site. If it fatals, this class is still in the code.

Also known as

JDocumentRaw · Joomla\CMS\Document\RawDocument · class alias · J prefix

Scan a ZIP for this Ask Infyways to fix it

JDOCUMENTXML-CLASS-001

JDocumentXml

JDocumentXml class name

JDocumentXml is a Joomla 3 global class. Joomla 4 still has an alias. Joomla 5 needs the Behaviour – Backward Compatibility plugin. Native Joomla 6 does not load that alias — you get Class "JDocumentXml" not found.

JDocumentXml → Joomla\CMS\Document\XmlDocument

Dies at Joomla 5 → 6

Dies at Joomla 5 → 6J3: Works nativelyJ4: Alias (old name still resolves)J6: Removed — fatalBC plugin: covers the class nameMechanical renameJoomla API

What you will see

Class "JDocumentXml" not found
Class 'JDocumentXml' not found
Failed to open stream: JDocumentXml

Symptoms people search

white screen after disabling compatibility plugin · class not found on Joomla 6 · works on Joomla 5 until I turn off backward compatibility

Replace this code

Swap JDocumentXml for Joomla\CMS\Document\XmlDocument.

Joomla 3

Remove or stop calling this

JDocumentXml::getInstance();
// or new JDocumentXml()

Joomla 4 / 6

Use this instead

use Joomla\CMS\Document\XmlDocument;

// Call the namespaced class. Do not keep the J prefix.

How to fix it

1Add a use statement for Joomla\CMS\Document\XmlDocument.
2Replace every JDocumentXml with the short class name from that use line.
3Disable Behaviour – Backward Compatibility on a Joomla 5 staging site. If it fatals, this class is still in the code.

Also known as

JDocumentXml · Joomla\CMS\Document\XmlDocument · class alias · J prefix

Scan a ZIP for this Ask Infyways to fix it

JERROR-CLASS-001

JError::raiseError()

JError / JException

JError was Joomla's old error stack. It was deleted in Joomla 4. Compatibility plugins do not restore it. Keep using PHP exceptions.

JError::raiseError() → throw new RuntimeException() / try-catch

Dies at Joomla 3 → 4

Dies at Joomla 3 → 4J3: Works nativelyJ4: Removed — fatalJ6: Removed — fatalBC plugin: no — already dead on J4Architecture change — no auto-fixJoomla API

What you will see

Class "JError" not found
Class "JException" not found

Symptoms people search

500 after save · error handling exploded on Joomla 4

Replace this code

Swap JError::raiseError() for throw new RuntimeException() / try-catch.

Joomla 3

Remove or stop calling this

JError::raiseError(500, 'Could not save');
$this->setError($db->getErrorMsg());

Joomla 4 / 6

Use this instead

throw new \RuntimeException('Could not save');
// Catch at the controller and enqueue a message

How to fix it

1Delete JError::raise* calls.
2Throw RuntimeException (or a domain exception) instead of setError().
3In controllers, catch and $app->enqueueMessage().

Also known as

JError · JException · raiseError · setError

There is no 1:1 swap for this one. The architecture changed. If you cannot rewrite it, Infyways can.

Scan a ZIP for this Ask Infyways to fix it

JERRORPAGE-CLASS-001

JErrorPage

JErrorPage class name

JErrorPage is a Joomla 3 global class. Joomla 4 still has an alias. Joomla 5 needs the Behaviour – Backward Compatibility plugin. Native Joomla 6 does not load that alias — you get Class "JErrorPage" not found.

JErrorPage → Joomla\CMS\Exception\ExceptionHandler

Dies at Joomla 5 → 6

Dies at Joomla 5 → 6J3: Works nativelyJ4: Alias (old name still resolves)J6: Removed — fatalBC plugin: covers the class nameMechanical renameJoomla API

What you will see

Class "JErrorPage" not found
Class 'JErrorPage' not found
Failed to open stream: JErrorPage

Symptoms people search

white screen after disabling compatibility plugin · class not found on Joomla 6 · works on Joomla 5 until I turn off backward compatibility

Replace this code

Swap JErrorPage for Joomla\CMS\Exception\ExceptionHandler.

Joomla 3

Remove or stop calling this

JErrorPage::getInstance();
// or new JErrorPage()

Joomla 4 / 6

Use this instead

use Joomla\CMS\Exception\ExceptionHandler;

// Call the namespaced class. Do not keep the J prefix.

How to fix it

1Add a use statement for Joomla\CMS\Exception\ExceptionHandler.
2Replace every JErrorPage with the short class name from that use line.
3Disable Behaviour – Backward Compatibility on a Joomla 5 staging site. If it fatals, this class is still in the code.

Also known as

JErrorPage · Joomla\CMS\Exception\ExceptionHandler · class alias · J prefix

Scan a ZIP for this Ask Infyways to fix it

JFACTORY-CLASS-001

JFactory

JFactory class name

JFactory is a Joomla 3 global class. Joomla 4 still has an alias. Joomla 5 needs the Behaviour – Backward Compatibility plugin. Native Joomla 6 does not load that alias — you get Class "JFactory" not found.

JFactory → Joomla\CMS\Factory

Dies at Joomla 5 → 6

Dies at Joomla 5 → 6J3: Works nativelyJ4: Alias (old name still resolves)J6: Removed — fatalBC plugin: covers the class nameMechanical renameJoomla API

What you will see

Class "JFactory" not found
Class 'JFactory' not found
Failed to open stream: JFactory

Symptoms people search

white screen after disabling compatibility plugin · class not found on Joomla 6 · works on Joomla 5 until I turn off backward compatibility · JFactory after upgrade · compat plugin required

Replace this code

Swap JFactory for Joomla\CMS\Factory.

Joomla 3

Remove or stop calling this

JFactory::getInstance();
// or new JFactory()

Joomla 4 / 6

Use this instead

use Joomla\CMS\Factory;

// Call the namespaced class. Do not keep the J prefix.

How to fix it

1Add a use statement for Joomla\CMS\Factory.
2Replace every JFactory with the short class name from that use line.
3Disable Behaviour – Backward Compatibility on a Joomla 5 staging site. If it fatals, this class is still in the code.

Also known as

JFactory · Joomla\CMS\Factory · class alias · J prefix

Scan a ZIP for this Ask Infyways to fix it

JFACTORY-GETAPPLICATION-001

JFactory::getApplication('site')

Factory::getApplication($client) arguments

You cannot ask Factory for a different client anymore. The argument is ignored or removed. There is one application.

JFactory::getApplication('site') → Factory::getApplication() with no client; then isClient()

Dies at Joomla 3 → 4

Dies at Joomla 3 → 4J3: Works nativelyJ4: Changed behaviourJ6: Changed behaviourBC plugin: not applicablePatch possible — review itJoomla API

Symptoms people search

always got site app in admin · getApplication site

Replace this code

Swap JFactory::getApplication('site') for Factory::getApplication() with no client; then isClient().

Joomla 3

Remove or stop calling this

$app = JFactory::getApplication('site');
$admin = JFactory::getApplication('administrator');

Joomla 4 / 6

Use this instead

$app = Factory::getApplication();
if ($app->isClient('administrator')) {}

How to fix it

1Call getApplication() with no arguments.
2Branch with isClient('site'|'administrator').

Also known as

getApplication('site') · getApplication('administrator')

Scan a ZIP for this Ask Infyways to fix it

JFACTORY-GETCACHE-001

JFactory::getCache()

Factory::getCache()

getCache() is a service locator. Joomla 4+ wants the cache controller factory.

JFactory::getCache() → Cache controller from the container

Dies at Joomla 5 → 6

Dies at Joomla 5 → 6J3: Works nativelyJ4: Deprecated — do not shipJ6: Deprecated — do not shipBC plugin: not applicablePatch possible — review itJoomla API

What you will see

Factory::getCache is deprecated

Symptoms people search

getCache deprecation

Replace this code

Swap JFactory::getCache() for Cache controller from the container.

Joomla 3

Remove or stop calling this

$cache = JFactory::getCache('com_lms', 'output');

Joomla 4 / 6

Use this instead

$cache = Factory::getContainer()->get(\Joomla\CMS\Cache\CacheControllerFactoryInterface::class)
    ->createCacheController('output', ['defaultgroup' => 'com_lms']);

How to fix it

1Resolve CacheControllerFactoryInterface from the container.

Also known as

getCache

Scan a ZIP for this Ask Infyways to fix it

JFACTORY-GETCONFIG-001

JFactory::getConfig()

Factory::getConfig()

Config lives on the application. Factory::getConfig() is deprecated.

JFactory::getConfig() → $app->getConfig() / $app->get('sitename')

Dies at Joomla 5 → 6

Dies at Joomla 5 → 6J3: Works nativelyJ4: Deprecated — do not shipJ6: Deprecated — do not shipBC plugin: not applicablePatch possible — review itJoomla API

What you will see

Factory::getConfig is deprecated

Symptoms people search

getConfig deprecation

Replace this code

Swap JFactory::getConfig() for $app->getConfig() / $app->get('sitename').

Joomla 3

Remove or stop calling this

$sitename = JFactory::getConfig()->get('sitename');

Joomla 4 / 6

Use this instead

$sitename = Factory::getApplication()->get('sitename');

How to fix it

1Prefer $app->get($key).
2Or $app->getConfig().

Also known as

getConfig

Scan a ZIP for this Ask Infyways to fix it

JFACTORY-GETDOCUMENT-001

JFactory::getDocument()

Factory::getDocument()

Document is owned by the application. Factory::getDocument() is deprecated.

JFactory::getDocument() → $app->getDocument()

Dies at Joomla 5 → 6

Dies at Joomla 5 → 6J3: Works nativelyJ4: Deprecated — do not shipJ6: Deprecated — do not shipBC plugin: not applicablePatch possible — review itJoomla API

What you will see

Factory::getDocument is deprecated

Symptoms people search

getDocument deprecation

Replace this code

Swap JFactory::getDocument() for $app->getDocument().

Joomla 3

Remove or stop calling this

$doc = JFactory::getDocument();
$doc->setTitle('Courses');

Joomla 4 / 6

Use this instead

$doc = Factory::getApplication()->getDocument();

How to fix it

1Use $app->getDocument().

Also known as

getDocument

Scan a ZIP for this Ask Infyways to fix it

JFACTORY-GETXML-001

JFactory::getXML()

Factory::getXml() / JXMLElement

JXMLElement and Factory::getXml were removed. PHP's SimpleXML is the replacement.

JFactory::getXML() → SimpleXMLElement

Dies at Joomla 3 → 4

Dies at Joomla 3 → 4J3: Works nativelyJ4: Removed — fatalJ6: Removed — fatalBC plugin: no — already dead on J4Patch possible — review itJoomla API

What you will see

Class "JXMLElement" not found
Call to undefined method Factory::getXml

Symptoms people search

manifest parse fatal

Replace this code

Swap JFactory::getXML() for SimpleXMLElement.

Joomla 3

Remove or stop calling this

$xml = JFactory::getXML($path, true);

Joomla 4 / 6

Use this instead

$xml = simplexml_load_file($path);
// or new \SimpleXMLElement($string)

How to fix it

1Use simplexml_load_file or SimpleXMLElement.
2Add error handling — SimpleXML returns false on bad XML.

Also known as

JXMLElement · getXML · getXml

Scan a ZIP for this Ask Infyways to fix it

JOPENSEARCH-CLASS-001

JOpenSearchDocument

JOpenSearchDocument class name

JOpenSearchDocument is a Joomla 3 global class. Joomla 4 still has an alias. Joomla 5 needs the Behaviour – Backward Compatibility plugin. Native Joomla 6 does not load that alias — you get Class "JOpenSearchDocument" not found.

JOpenSearchDocument → Joomla\CMS\Document\Opensearch\OpensearchDocument

Dies at Joomla 5 → 6

Dies at Joomla 5 → 6J3: Works nativelyJ4: Alias (old name still resolves)J6: Removed — fatalBC plugin: covers the class nameMechanical renameJoomla API

What you will see

Class "JOpenSearchDocument" not found
Class 'JOpenSearchDocument' not found
Failed to open stream: JOpenSearchDocument

Symptoms people search

white screen after disabling compatibility plugin · class not found on Joomla 6 · works on Joomla 5 until I turn off backward compatibility

Replace this code

Swap JOpenSearchDocument for Joomla\CMS\Document\Opensearch\OpensearchDocument.

Joomla 3

Remove or stop calling this

JOpenSearchDocument::getInstance();
// or new JOpenSearchDocument()

Joomla 4 / 6

Use this instead

use Joomla\CMS\Document\Opensearch\OpensearchDocument;

// Call the namespaced class. Do not keep the J prefix.

How to fix it

1Add a use statement for Joomla\CMS\Document\Opensearch\OpensearchDocument.
2Replace every JOpenSearchDocument with the short class name from that use line.
3Disable Behaviour – Backward Compatibility on a Joomla 5 staging site. If it fatals, this class is still in the code.

Also known as

JOpenSearchDocument · Joomla\CMS\Document\Opensearch\OpensearchDocument · class alias · J prefix

Scan a ZIP for this Ask Infyways to fix it

JRESPONSEJSON-CLASS-001

JResponseJson

JResponseJson class name

JResponseJson is a Joomla 3 global class. Joomla 4 still has an alias. Joomla 5 needs the Behaviour – Backward Compatibility plugin. Native Joomla 6 does not load that alias — you get Class "JResponseJson" not found.

JResponseJson → Joomla\CMS\Response\JsonResponse

Dies at Joomla 5 → 6

Dies at Joomla 5 → 6J3: Works nativelyJ4: Alias (old name still resolves)J6: Removed — fatalBC plugin: covers the class nameMechanical renameJoomla API

What you will see

Class "JResponseJson" not found
Class 'JResponseJson' not found
Failed to open stream: JResponseJson

Symptoms people search

white screen after disabling compatibility plugin · class not found on Joomla 6 · works on Joomla 5 until I turn off backward compatibility

Replace this code

Swap JResponseJson for Joomla\CMS\Response\JsonResponse.

Joomla 3

Remove or stop calling this

JResponseJson::getInstance();
// or new JResponseJson()

Joomla 4 / 6

Use this instead

use Joomla\CMS\Response\JsonResponse;

// Call the namespaced class. Do not keep the J prefix.

How to fix it

1Add a use statement for Joomla\CMS\Response\JsonResponse.
2Replace every JResponseJson with the short class name from that use line.
3Disable Behaviour – Backward Compatibility on a Joomla 5 staging site. If it fatals, this class is still in the code.

Also known as

JResponseJson · Joomla\CMS\Response\JsonResponse · class alias · J prefix

Scan a ZIP for this Ask Infyways to fix it

JVERSION-CLASS-001

JVersion

JVersion class name

JVersion is a Joomla 3 global class. Joomla 4 still has an alias. Joomla 5 needs the Behaviour – Backward Compatibility plugin. Native Joomla 6 does not load that alias — you get Class "JVersion" not found.

JVersion → Joomla\CMS\Version

Dies at Joomla 5 → 6

Dies at Joomla 5 → 6J3: Works nativelyJ4: Alias (old name still resolves)J6: Removed — fatalBC plugin: covers the class nameMechanical renameJoomla API

What you will see

Class "JVersion" not found
Class 'JVersion' not found
Failed to open stream: JVersion

Symptoms people search

white screen after disabling compatibility plugin · class not found on Joomla 6 · works on Joomla 5 until I turn off backward compatibility

Replace this code

Swap JVersion for Joomla\CMS\Version.

Joomla 3

Remove or stop calling this

JVersion::getInstance();
// or new JVersion()

Joomla 4 / 6

Use this instead

use Joomla\CMS\Version;

// Call the namespaced class. Do not keep the J prefix.

How to fix it

1Add a use statement for Joomla\CMS\Version.
2Replace every JVersion with the short class name from that use line.
3Disable Behaviour – Backward Compatibility on a Joomla 5 staging site. If it fatals, this class is still in the code.

Also known as

JVersion · Joomla\CMS\Version · class alias · J prefix

Scan a ZIP for this Ask Infyways to fix it

JVERSION-RELEASE-001

JVersion::RELEASE

JVersion::RELEASE / DEV_LEVEL / BUILD

The old version constants were removed. JVERSION string still exists but RELEASE/DEV_LEVEL/BUILD do not.

JVersion::RELEASE → MAJOR_VERSION, MINOR_VERSION, PATCH_VERSION

Dies at Joomla 3 → 4

Dies at Joomla 3 → 4J3: Works nativelyJ4: Removed — fatalJ6: Removed — fatalBC plugin: no — already dead on J4Patch possible — review itJoomla API

What you will see

Undefined class constant RELEASE
Undefined class constant DEV_LEVEL

Symptoms people search

version check always wrong · JVersion::RELEASE

Replace this code

Swap JVersion::RELEASE for MAJOR_VERSION, MINOR_VERSION, PATCH_VERSION.

Joomla 3

Remove or stop calling this

if (JVERSION == '3.10') {}
echo JVersion::RELEASE . '.' . JVersion::DEV_LEVEL;

Joomla 4 / 6

Use this instead

use Joomla\CMS\Version;
if (Version::MAJOR_VERSION === 4) {}
echo Version::MAJOR_VERSION . '.' . Version::MINOR_VERSION;

How to fix it

1Use Version::MAJOR_VERSION / MINOR_VERSION / PATCH_VERSION.
2Do not parse JVERSION as a Joomla 3 string.

Also known as

JVersion::RELEASE · DEV_LEVEL · JVERSION

Scan a ZIP for this Ask Infyways to fix it

JWEB-CLASS-001

JWeb

JWeb was an old application base. It is obsolete in Joomla 4.

JWeb → WebApplication

Dies at Joomla 3 → 4

Dies at Joomla 3 → 4J3: Works nativelyJ4: Removed — fatalJ6: Removed — fatalBC plugin: no — already dead on J4You rewrite thisJoomla API

What you will see

Class "JWeb" not found

Symptoms people search

custom app bootstrap fatal

Replace this code

Swap JWeb for WebApplication.

Joomla 3

Remove or stop calling this

class MyCliWeb extends JWeb {}

Joomla 4 / 6

Use this instead

Extend Joomla\CMS\Application\WebApplication (or CliApplication for CLI).

How to fix it

1Extend WebApplication / CliApplication.
2Implement doExecute() if the class is abstract.

Also known as

JWeb

There is no 1:1 swap for this one. The architecture changed. If you cannot rewrite it, Infyways can.

Scan a ZIP for this Ask Infyways to fix it

YEARLY-ALIASES-001

JFactory / JText / JHtml everywhere

“It still works with J* aliases” is not Joomla 6 native

Years of “it still works” is why Joomla 6 upgrades white-screen. Aliases are a crutch, not the destination.

JFactory / JText / JHtml everywhere → Namespaced classes, BC plugin off

Dies at Joomla 5 → 6

Dies at Joomla 5 → 6J3: Works nativelyJ4: Alias (old name still resolves)J6: Removed — fatalBC plugin: covers the class nameYou rewrite thisJoomla API

What you will see

Class "JFactory" not found

Symptoms people search

it still works on joomla 5 · aliases are fine · we will rename later

Replace this code

Swap JFactory / JText / JHtml everywhere for Namespaced classes, BC plugin off.

Joomla 3

Remove or stop calling this

// “We’ll rename later. Joomla 4 still has aliases.”

Joomla 4 / 6

Use this instead

Disable Behaviour – Backward Compatibility on Joomla 5 staging. Every Class "J…" not found is remaining debt. Native Joomla 6 has no J* globals.

How to fix it

1Treat every J* as a ticket.
2Use this reference A–Z, then scan the ZIP.
3Do not ship a “Joomla 6” extension that still needs the J5 compat plugin.

Also known as

class alias · J prefix · temporary aliases · native joomla 6

Scan a ZIP for this Ask Infyways to fix it