# Log4j2 Appender
This module provides a Log4j2 [appender](https://logging.apache.org/log4j/2.x/manual/appenders.html)
which forwards Log4j2 log events to the
[OpenTelemetry Log SDK](https://github.com/open-telemetry/opentelemetry-java/tree/main/sdk/logs).
To use it, add the following modules to your application's classpath.
Replace `OPENTELEMETRY_VERSION` with the latest
stable [release](https://search.maven.org/search?q=g:io.opentelemetry.instrumentation).
**Maven**
```xml
io.opentelemetry.instrumentation
opentelemetry-log4j-appender-2.16
OPENTELEMETRY_VERSION
```
**Gradle**
```kotlin
dependencies {
runtimeOnly("io.opentelemetry.instrumentation:opentelemetry-log4j-appender-2.16:OPENTELEMETRY_VERSION")
}
```
The following demonstrates how you might configure the appender in your `log4j.xml` configuration:
```xml
```
Next, associate the `OpenTelemetryAppender` configured via `log4j2.xml` with
an `SdkLogEmitterProvider` in your application:
```
SdkLogEmitterProvider logEmitterProvider =
SdkLogEmitterProvider.builder()
.setResource(Resource.create(...))
.addLogProcessor(...)
.build();
OpenTelemetryAppender.setSdkLogEmitterProvider(logEmitterProvider);
```
In this example Log4j2 log events will be sent to both the console appender and
the `OpenTelemetryAppender`, which will drop the logs until
`OpenTelemetryAppender.setSdkLogEmitterProvider(..)` is called. Once initialized, logs will be
emitted to a `LogEmitter` obtained from the `SdkLogEmitterProvider`.