////
    Licensed to the Apache Software Foundation (ASF) under one or more
    contributor license agreements.  See the NOTICE file distributed with
    this work for additional information regarding copyright ownership.
    The ASF licenses this file to You under the Apache License, Version 2.0
    (the "License"); you may not use this file except in compliance with
    the License.  You may obtain a copy of the License at

         http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
////
[id=log4j1.compatibility]
== `log4j1.compatibility`

[cols="1h,5"]
|===
| Env. variable | LOG4J_COMPATIBILITY
| Type          | `boolean`
| Default value | `false`
|===

If set to `true`, Log4j 2 will scan the classpath to find Log4j 1 configuration files in the following standard locations:

* `log4j-test.properties`,
* `log4j-test.xml`,
* `log4j.properties`,
* `log4j.xml`.

[id=log4j.configuration]
== `log4j.configuration`

[cols="1h,5"]
|===
| Env. variable
| LOG4J_CONFIGURATION_FILE

| Type
|
https://docs.oracle.com/javase/{java-target-version}/docs/api/java/nio/file/Path.html[Path]
or
https://docs.oracle.com/javase/{java-target-version}/docs/api/java/net/URI.html[URI]

| Default value
| `null`
|===

If not `null`, Log4j 2 will try to retrieve a **Log4j 1** configuration file from the given location.
The configuration file name must end in `.properties` (Log4j 1 properties format) or `.xml` (Log4j 1 XML format).
See also
xref:migrate-from-log4j1.adoc##limitations-of-the-log4j-1-x-bridge[limitations of Log4j 1 configuration compatibility layer].
