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Adds examples for Log4j 2's JSON format log template layout #29985

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Jul 8, 2025
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Adds examples for Log4j 2's JSON format log template layout #29985

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Adds examples for Log4j 2's JSON format log template layout
joon-shin-ddhq Jun 17, 2025
642bf7b
Update java.md
estherk15 Jul 8, 2025
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Update content/en/logs/log_collection/java.md
estherk15 Jul 8, 2025
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76 changes: 70 additions & 6 deletions content/en/logs/log_collection/java.md
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Expand Up @@ -152,7 +152,62 @@ Log4j 2 includes a JSON layout.
{{< /code-block >}}
{{% /collapse-content %}}

2. Add the JSON layout dependencies to your `pom.xml`. For example:
2. Add the JSON layout template file (such as `MyLayout.json`) in the `src/main/resources` directory of your Java project. For example:
```json
{
"timestamp":{
"$resolver":"timestamp",
"pattern":{
"format":"yyyy-MM-dd'T'HH:mm:ss.SSS'Z'",
"timeZone":"UTC"
}
},
"status":{
"$resolver":"level",
"field":"name"
},
"thread_name":{
"$resolver":"thread",
"field":"name"
},
"logger_name":{
"$resolver":"logger",
"field":"name"
},
"message":{
"$resolver":"message",
"stringified":true
},
"exception_class":{
"$resolver":"exception",
"field":"className"
},
"exception_message":{
"$resolver":"exception",
"field":"message"
},
"stack_trace":{
"$resolver":"exception",
"field":"stackTrace",
"stackTrace":{
"stringified":true
}
},
"host":"${hostName}",
"service":"${env:DD_SERVICE}",
"version":"${env:DD_VERSION}",
"dd.trace_id":{
"$resolver":"mdc",
"key":"dd.trace_id"
},
"dd.span_id":{
"$resolver":"mdc",
"key":"dd.span_id"
}
}
```

3. Add the JSON layout dependencies to your `pom.xml`. For example:
```xml
<dependency>
<groupId>org.apache.logging.log4j</groupId>
Expand Down Expand Up @@ -240,10 +295,6 @@ writer.field.dd.env = {context: dd.env}
{{% /tab %}}
{{< /tabs >}}

#### Inject trace IDs into your logs

If APM is enabled for this application, you can correlate logs and traces by enabling trace ID injection. See [Connecting Java Logs and Traces][3] for more information.

### Raw format

{{< tabs >}}
Expand Down Expand Up @@ -341,7 +392,20 @@ writer.file = log.txt

If APM is enabled for this application, you can correlate logs and traces by enabling trace ID injection. See [Connecting Java Logs and Traces][3].

If you are _not_ correlating logs and traces, you can remove the MDC placeholders (`%X{dd.trace_id} %X{dd.span_id}`) from the log patterns included in the above configuration examples.
If you are _not_ correlating logs and traces, remove the MDC placeholders (`%X{dd.trace_id} %X{dd.span_id}`) from the log patterns included in the previous configuration examples.

For example, if you are using Log4j 2 but not correlating logs and traces, remove the following block from the example log layout template, `MyLayout.json`:

```json
"dd.trace_id":{
"$resolver":"mdc",
"key":"dd.trace_id"
},
"dd.span_id":{
"$resolver":"mdc",
"key":"dd.span_id"
}
```


## Configure the Datadog Agent
Expand Down
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