Send logs from Java to SigNoz using OpenTelemetry

Prerequisites

Java 8 or higher
An instance of SigNoz (either Cloud or Self-Hosted)

Choosing a Log Collection Method

There are two primary ways to send logs from your Java application to SigNoz:

Application-level Collection (OTLP):
Your application sends logs directly to SigNoz using the OpenTelemetry Java Agent.
Recommended for: Most users. It provides automatic trace-log correlation, rich metadata, and requires no changing of infrastructure.
Infrastructure-level Collection (Stdout/Stderr):
Your application writes logs to the console, and an agent running on the node/cluster collects them.
Recommended for: Kubernetes environments, legacy applications you can't reconfigure, or when you want strictly separated logging concerns.

This guide focuses on Application-level Collection (OTLP).

Send logs to SigNoz

The OpenTelemetry Java Agent automatically captures logs from popular logging frameworks like Log4j 2, Logback, and java.util.logging (JUL) and sends them to SigNoz.

Step 1: Download the Java Agent

Download the latest opentelemetry-javaagent.jar:

wget https://github.com/open-telemetry/opentelemetry-java-instrumentation/releases/latest/download/opentelemetry-javaagent.jar

Step 2: Run the application

Set the environment variables and run your application:

export OTEL_EXPORTER_OTLP_ENDPOINT="https://ingest.<region>.signoz.cloud:443"
export OTEL_EXPORTER_OTLP_HEADERS="signoz-ingestion-key=<your-ingestion-key>"
export OTEL_SERVICE_NAME="java-app"

java -javaagent:./opentelemetry-javaagent.jar -jar your-app.jar

Verify these values:

<region>: Your SigNoz Cloud region.
<your-ingestion-key>: Your ingestion key.

If using a local OTel Collector (e.g., self-hosted), use:

export OTEL_EXPORTER_OTLP_ENDPOINT="http://localhost:4317"
export OTEL_SERVICE_NAME="java-app"

java -javaagent:./opentelemetry-javaagent.jar -jar your-app.jar

Add these environment variables to your deployment manifest:

env:
  - name: OTEL_EXPORTER_OTLP_ENDPOINT
    value: 'https://ingest.<region>.signoz.cloud:443'
  - name: OTEL_EXPORTER_OTLP_HEADERS
    value: 'signoz-ingestion-key=<your-ingestion-key>'
  - name: OTEL_SERVICE_NAME
    value: 'java-app'
  - name: JAVA_TOOL_OPTIONS
    value: '-javaagent:/path/to/opentelemetry-javaagent.jar'

Verify these values:

<region>: Your SigNoz Cloud region.
<your-ingestion-key>: Your ingestion key.

Note: You need to ensure the opentelemetry-javaagent.jar is available in the container or added via an init container / volume.

⚠️ Warning

Avoiding Duplicate Logs

If using the k8s-infra chart (which auto-collects container logs), disable log collection for this application to prevent duplicates.

See how to disable log collection →

Create a Dockerfile:

Dockerfile

FROM eclipse-temurin:17-jre

WORKDIR /app

# Download the OpenTelemetry Java Agent
ADD https://github.com/open-telemetry/opentelemetry-java-instrumentation/releases/latest/download/opentelemetry-javaagent.jar /app/opentelemetry-javaagent.jar

# Copy your application JAR
COPY target/your-app.jar /app/app.jar

# Set environment variables
ENV OTEL_EXPORTER_OTLP_ENDPOINT="https://ingest.<region>.signoz.cloud:443"
ENV OTEL_EXPORTER_OTLP_HEADERS="signoz-ingestion-key=<your-ingestion-key>"
ENV OTEL_SERVICE_NAME="java-app"

# Configure the agent
ENV JAVA_TOOL_OPTIONS="-javaagent:/app/opentelemetry-javaagent.jar"

CMD ["java", "-jar", "/app/app.jar"]

Build and run:

docker build -t java-app .
docker run -p 8080:8080 java-app

Replace the placeholders:

<region>: Your SigNoz Cloud region.
<your-ingestion-key>: Your ingestion key.

⚠️ Warning

Avoiding Duplicate Logs

If you have a log driver or a collector picking up Docker container logs (stdout), you might see duplicate logs in SigNoz. To avoid this, either disable container log collection for this service or use only one method.

Set environment variables in PowerShell:

$env:OTEL_EXPORTER_OTLP_ENDPOINT = "https://ingest.<region>.signoz.cloud:443"
$env:OTEL_EXPORTER_OTLP_HEADERS = "signoz-ingestion-key=<your-ingestion-key>"
$env:OTEL_SERVICE_NAME = "java-app"

java -javaagent:./opentelemetry-javaagent.jar -jar your-app.jar

Verify these values:

<region>: Your SigNoz Cloud region.
<your-ingestion-key>: Your ingestion key.

Log Correlation

The OpenTelemetry Java Agent automatically injects trace_id and span_id into your logs when a tracing context is active, allowing you to correlate logs with traces in SigNoz.

✅ Info

By default, the Java Agent collects traces, metrics, and logs. To collect only logs, disable traces and metrics:

export OTEL_TRACES_EXPORTER="none"
export OTEL_METRICS_EXPORTER="none"

Step 1: Add dependencies

Add the following OpenTelemetry dependencies to your project.

<dependencyManagement>
  <dependencies>
    <dependency>
      <groupId>io.opentelemetry</groupId>
      <artifactId>opentelemetry-bom</artifactId>
      <version>1.57.0</version>
      <type>pom</type>
      <scope>import</scope>
    </dependency>
    <dependency>
      <groupId>io.opentelemetry.instrumentation</groupId>
      <artifactId>opentelemetry-instrumentation-bom-alpha</artifactId>
      <version>2.23.0-alpha</version>
      <type>pom</type>
      <scope>import</scope>
    </dependency>
  </dependencies>
</dependencyManagement>

<dependencies>
  <!-- OpenTelemetry SDK -->
  <dependency>
    <groupId>io.opentelemetry</groupId>
    <artifactId>opentelemetry-sdk</artifactId>
  </dependency>
  <!-- OpenTelemetry Autoconfigure -->
  <dependency>
    <groupId>io.opentelemetry</groupId>
    <artifactId>opentelemetry-sdk-extension-autoconfigure</artifactId>
    <version>1.57.0</version>
  </dependency>
  <!-- OpenTelemetry Exporter -->
  <dependency>
    <groupId>io.opentelemetry</groupId>
    <artifactId>opentelemetry-exporter-otlp</artifactId>
  </dependency>
  <!-- Semantic Conventions -->
  <dependency>
    <groupId>io.opentelemetry.semconv</groupId>
    <artifactId>opentelemetry-semconv</artifactId>
  </dependency>
  <!-- Logback Appender -->
  <dependency>
    <groupId>io.opentelemetry.instrumentation</groupId>
    <artifactId>opentelemetry-logback-appender-1.0</artifactId>
  </dependency>
</dependencies>

dependencies {
    implementation platform('io.opentelemetry:opentelemetry-bom:1.57.0')
    implementation platform('io.opentelemetry.instrumentation:opentelemetry-instrumentation-bom-alpha:2.23.0-alpha')

    // OpenTelemetry SDK
    implementation 'io.opentelemetry:opentelemetry-sdk'

    // OpenTelemetry Autoconfigure
    implementation 'io.opentelemetry:opentelemetry-sdk-extension-autoconfigure:1.57.0'

    // OpenTelemetry Exporter
    implementation 'io.opentelemetry:opentelemetry-exporter-otlp'

    // Semantic Conventions
    implementation 'io.opentelemetry.semconv:opentelemetry-semconv'

    // Logback Appender
    implementation 'io.opentelemetry.instrumentation:opentelemetry-logback-appender-1.0'
}

Step 2: Set environment variables

export OTEL_EXPORTER_OTLP_ENDPOINT="https://ingest.<region>.signoz.cloud:443"
export OTEL_EXPORTER_OTLP_HEADERS="signoz-ingestion-key=<your-ingestion-key>"
export OTEL_SERVICE_NAME="java-manual-app"

Verify these values:

<region>: Your SigNoz Cloud region.
<your-ingestion-key>: Your ingestion key.

Add these environment variables to your deployment manifest:

env:
  - name: OTEL_EXPORTER_OTLP_ENDPOINT
    value: 'https://ingest.<region>.signoz.cloud:443'
  - name: OTEL_EXPORTER_OTLP_HEADERS
    value: 'signoz-ingestion-key=<your-ingestion-key>'
  - name: OTEL_SERVICE_NAME
    value: 'java-manual-app'

Verify these values:

<region>: Your SigNoz Cloud region.
<your-ingestion-key>: Your ingestion key.

⚠️ Warning

Avoiding Duplicate Logs

If using the k8s-infra chart (which auto-collects container logs), disable log collection for this application to prevent duplicates.

See how to disable log collection →

Create a Dockerfile in your project root:

Dockerfile

FROM eclipse-temurin:17-jre

WORKDIR /app

# Copy your application JAR
COPY target/your-app.jar /app/app.jar

# Set OpenTelemetry environment variables
ENV OTEL_EXPORTER_OTLP_ENDPOINT="https://ingest.<region>.signoz.cloud:443"
ENV OTEL_EXPORTER_OTLP_HEADERS="signoz-ingestion-key=<your-ingestion-key>"
ENV OTEL_SERVICE_NAME="java-manual-app"

CMD ["java", "-jar", "/app/app.jar"]

Build and run the container:

docker build -t java-manual-app .
docker run java-manual-app

Verify these values:

<region>: Your SigNoz Cloud region.
<your-ingestion-key>: Your ingestion key.

⚠️ Warning

Avoiding Duplicate Logs

Set environment variables in PowerShell:

$env:OTEL_EXPORTER_OTLP_ENDPOINT = "https://ingest.<region>.signoz.cloud:443"
$env:OTEL_EXPORTER_OTLP_HEADERS = "signoz-ingestion-key=<your-ingestion-key>"
$env:OTEL_SERVICE_NAME = "java-manual-app"

Verify these values:

<region>: Your SigNoz Cloud region.
<your-ingestion-key>: Your ingestion key.

Step 3: Initialize OpenTelemetry SDK

Create a file named src/main/java/com/example/OpenTelemetryConfig.java to initialize the OpenTelemetry SDK. You must initialize both the LoggerProvider (for logs) and the TracerProvider (for correlation).

src/main/java/com/example/OpenTelemetryConfig.java

package com.example;

import io.opentelemetry.api.OpenTelemetry;
import io.opentelemetry.sdk.autoconfigure.AutoConfiguredOpenTelemetrySdk;

public class OpenTelemetryConfig {

    public static OpenTelemetry init() {
        AutoConfiguredOpenTelemetrySdk autoConfiguredSdk = AutoConfiguredOpenTelemetrySdk.initialize();
        return autoConfiguredSdk.getOpenTelemetrySdk();
    }
}

Step 4: Configure Logback

Create a file named src/main/resources/logback.xml and add the OpenTelemetryAppender to bridge logs to the OpenTelemetry SDK.

src/main/resources/logback.xml

<configuration>
  <appender name="OTEL" class="io.opentelemetry.instrumentation.logback.appender.v1_0.OpenTelemetryAppender">
    <captureExperimentalAttributes>true</captureExperimentalAttributes>
    <captureKeyValuePairAttributes>true</captureKeyValuePairAttributes>
  </appender>

  <appender name="CONSOLE" class="ch.qos.logback.core.ConsoleAppender">
    <encoder>
      <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
    </encoder>
  </appender>

  <root level="INFO">
    <appender-ref ref="OTEL" />
    <appender-ref ref="CONSOLE" />
  </root>
</configuration>

Step 5: Instrument usage with Log Correlation

Initialize the SDK at the start of your application. When you create spans and make them current, the OpenTelemetry appender will automatically add the trace_id and span_id to your logs.

Create or update your main application file src/main/java/com/example/Application.java.

src/main/java/com/example/Application.java

package com.example;

import io.opentelemetry.api.GlobalOpenTelemetry;
import io.opentelemetry.api.trace.Span;
import io.opentelemetry.api.trace.Tracer;
import io.opentelemetry.context.Scope;
import io.opentelemetry.instrumentation.logback.appender.v1_0.OpenTelemetryAppender;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class Application {
    private static final Logger logger = LoggerFactory.getLogger(Application.class);

    public static void main(String[] args) {
        // Initialize OpenTelemetry
        OpenTelemetryConfig.init();

        // Install the Logback appender using GlobalOpenTelemetry
        OpenTelemetryAppender.install(GlobalOpenTelemetry.get());
        logger.info("Application started (no active span)");

        // Create span for correlation
        Tracer tracer = GlobalOpenTelemetry.getTracer("my-app");
        Span span = tracer.spanBuilder("my-span").startSpan();

        try (Scope scope = span.makeCurrent()) {
            logger.info("Processing data within a span...");
            doWork();
        } finally {
            span.end();
        }

        logger.info("Application finished");
    }

    private static void doWork() {
        logger.warn("Simulated work log - also correlated!");
    }
}

Step 6: Build and Run

Build your project and run the application.

mvn clean package
java -jar target/your-app-1.0-SNAPSHOT.jar

Validate Logs

Captured logs can be viewed in the Logs Explorer section.

Setup OpenTelemetry Collector (Optional)

What is the OpenTelemetry Collector?

Think of the OTel Collector as a middleman between your app and SigNoz. Instead of your application sending data directly to SigNoz, it sends everything to the Collector first, which then forwards it along.

Why use it?

Cleaning up data — Filter out noisy traces you don't care about, or remove sensitive info before it leaves your servers.
Keeping your app lightweight — Let the Collector handle batching, retries, and compression instead of your application code.
Adding context automatically — The Collector can tag your data with useful info like which Kubernetes pod or cloud region it came from.
Future flexibility — Want to send data to multiple backends later? The Collector makes that easy without changing your app.

See Switch from direct export to Collector for step-by-step instructions to convert your setup.

For more details, see Why use the OpenTelemetry Collector? and the Collector configuration guide.

Troubleshooting

Why are my logs not appearing?

Ensure OTEL_LOGS_EXPORTER is set to otlp (for Auto-Instrumentation).
Verify the OTEL_EXPORTER_OTLP_ENDPOINT is correct and reachable.
Check the console output for any OTel-related errors.
If using logback.xml, ensure the OTEL appender is added to <root>.

Next Steps

Get Help

If you need help with the steps in this topic, please reach out to us on SigNoz Community Slack.

If you are a SigNoz Cloud user, please use in product chat support located at the bottom right corner of your SigNoz instance or contact us at cloud-support@signoz.io.

Send logs from Java to SigNoz using OpenTelemetry

Prerequisites

Choosing a Log Collection Method

Send logs to SigNoz

Step 1: Download the Java Agent

Step 2: Run the application

Log Correlation

Step 1: Add dependencies

Step 2: Set environment variables

Step 3: Initialize OpenTelemetry SDK

Step 4: Configure Logback

Step 5: Instrument usage with Log Correlation

Step 6: Build and Run

Validate Logs

Setup OpenTelemetry Collector (Optional)

What is the OpenTelemetry Collector?

Why use it?

Troubleshooting

Why are my logs not appearing?

Next Steps

Get Help

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