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Monitoring JVM Metrics with ClickStack

TL;DR

This guide shows you how to monitor JVM applications with ClickStack using the OpenTelemetry Java agent to collect metrics. You'll learn how to:

  • Attach the OpenTelemetry Java agent to your JVM application
  • Configure the agent to send metrics to ClickStack via OTLP
  • Use a pre-built dashboard to visualize heap memory, garbage collection, threads, and CPU

A demo dataset with sample metrics is available if you want to test the integration before instrumenting your production applications.

Time Required: 5-10 minutes

Integration with existing JVM application​

This section covers configuring your existing JVM application to send metrics to ClickStack using the OpenTelemetry Java agent.

If you would like to test the integration before configuring your production setup, you can test with our demo dataset in the demo dataset section.

Prerequisites​
  • ClickStack instance running
  • Existing Java application (Java 8+)
  • Access to modify JVM startup arguments

Get ClickStack API key​

The OpenTelemetry Java agent sends data to ClickStack's OTLP endpoint, which requires authentication.

  1. Open HyperDX at your ClickStack URL (e.g., http://localhost:8080)
  2. Create an account or log in if needed
  3. Navigate to Team Settings → API Keys
  4. Copy your Ingestion API Key

Download OpenTelemetry Java agent​

Download the OpenTelemetry Java agent JAR file:

curl -L -O https://github.com/open-telemetry/opentelemetry-java-instrumentation/releases/download/v2.22.0/opentelemetry-javaagent.jar

This downloads the agent to your current directory. You can place it wherever makes sense for your deployment (e.g., /opt/opentelemetry/ or alongside your application JAR).

Configure JVM startup arguments​

Add the Java agent to your JVM startup command. The agent automatically collects JVM metrics and sends them to ClickStack.

Option 1: Command line flags​
java -javaagent:opentelemetry-javaagent.jar \
  -Dotel.service.name=my-java-app \
  -Dotel.exporter.otlp.endpoint=http://localhost:4318 \
  -Dotel.exporter.otlp.protocol=http/protobuf \
  -Dotel.exporter.otlp.headers="authorization=YOUR_API_KEY" \
  -Dotel.metrics.exporter=otlp \
  -Dotel.logs.exporter=none \
  -Dotel.traces.exporter=none \
  -jar my-application.jar

Replace the following:

  • opentelemetry-javaagent.jar → Full path to the agent JAR (e.g., /opt/opentelemetry/opentelemetry-javaagent.jar)
  • my-java-app → A meaningful name for your service (e.g., payment-service, user-api)
  • YOUR_API_KEY → Your ClickStack API key from the command above
  • my-application.jar → Your application's JAR file name
  • http://localhost:4318 → Your ClickStack endpoint (use localhost:4318 if ClickStack runs on the same machine, otherwise use http://your-clickstack-host:4318)
Option 2: Environment variables​

Alternatively, use environment variables:

export JAVA_TOOL_OPTIONS="-javaagent:opentelemetry-javaagent.jar"
export OTEL_SERVICE_NAME="my-java-app"
export OTEL_EXPORTER_OTLP_ENDPOINT="http://localhost:4318"
export OTEL_EXPORTER_OTLP_PROTOCOL="http/protobuf"
export OTEL_EXPORTER_OTLP_HEADERS="authorization=YOUR_API_KEY"
export OTEL_METRICS_EXPORTER="otlp"
export OTEL_LOGS_EXPORTER="none"
export OTEL_TRACES_EXPORTER="none"

java -jar my-application.jar

Replace the following:

  • opentelemetry-javaagent.jar → Full path to the agent JAR
  • my-java-app → Your service name
  • YOUR_API_KEY → Your ClickStack API key
  • http://localhost:4318 → Your ClickStack endpoint
  • my-application.jar → Your application's JAR file name
Tip

The OpenTelemetry Java agent automatically collects these JVM metrics:

  • Memory: jvm.memory.used, jvm.memory.limit, jvm.memory.committed, jvm.memory.used_after_last_gc
  • Garbage Collection: jvm.gc.duration
  • Threads: jvm.thread.count
  • Classes: jvm.class.count, jvm.class.loaded, jvm.class.unloaded
  • CPU: jvm.cpu.time, jvm.cpu.count

Verify metrics in HyperDX​

Once your application is running with the agent, verify metrics are flowing to ClickStack:

  1. Open HyperDX at http://localhost:8080 (or your ClickStack URL)
  2. Navigate to Chart Explorer
  3. Search for metrics starting with jvm. (e.g., jvm.memory.used, jvm.gc.duration, jvm.thread.count)

Demo dataset​

For users who want to test the JVM metrics integration before instrumenting their applications, we provide a sample dataset with pre-generated metrics showing realistic JVM behavior from a medium-sized microservice with steady moderate traffic.

Download the sample dataset​

# Download gauge metrics (memory, threads, CPU, classes)
curl -O https://datasets-documentation.s3.eu-west-3.amazonaws.com/clickstack-integrations/jvm/jvm-metrics-gauge.jsonl

# Download sum metrics (GC events)
curl -O https://datasets-documentation.s3.eu-west-3.amazonaws.com/clickstack-integrations/jvm/jvm-metrics-sum.jsonl

The dataset includes 24 hours of JVM metrics showing:

  • Heap memory growth with periodic garbage collection events
  • Thread count variations
  • Realistic GC pause times
  • Class loading activity
  • CPU utilization patterns

Start ClickStack​

If you don't already have ClickStack running:

docker run -d --name clickstack \
  -p 8080:8080 -p 4317:4317 -p 4318:4318 \
  clickhouse/clickstack-all-in-one:latest

Wait a few moments for ClickStack to fully start up.

Import the demo dataset​

# Import gauge metrics (memory, threads, CPU, classes)
docker exec -i clickstack clickhouse-client --query="
  INSERT INTO default.otel_metrics_gauge FORMAT JSONEachRow
" < jvm-metrics-gauge.jsonl

# Import sum metrics (GC events)
docker exec -i clickstack clickhouse-client --query="
  INSERT INTO default.otel_metrics_sum FORMAT JSONEachRow
" < jvm-metrics-sum.jsonl

This imports the metrics directly into ClickStack's metrics tables.

Verify the demo data​

Once imported:

  1. Open HyperDX at http://localhost:8080 and log in (create an account if needed)
  2. Navigate to the Search view and set source to Metrics
  3. Set the time range to 2025-12-06 14:00:00 - 2025-12-09 14:00:00
  4. Search for jvm.memory.used or jvm.gc.duration

You should see metrics for the demo service.

Timezone Display

HyperDX displays timestamps in your browser's local timezone. The demo data spans 2025-12-07 14:00:00 - 2025-12-08 14:00:00 (UTC). Set your time range to 2025-12-06 14:00:00 - 2025-12-09 14:00:00 to ensure you see the demo metrics regardless of your location. Once you see the metrics, you can narrow the range to a 24-hour period for clearer visualizations.

Dashboards and visualization​

To help you monitor JVM applications with ClickStack, we provide a pre-built dashboard with essential visualizations for JVM metrics.

Download the dashboard configuration​

Import the pre-built dashboard​

  1. Open HyperDX and navigate to the Dashboards section
  2. Click Import Dashboard in the upper right corner under the ellipses
  1. Upload the jvm-metrics-dashboard.json file and click Finish Import

View the dashboard​

The dashboard will be created with all visualizations pre-configured:

Note

For the demo dataset, set the time range to 2025-12-07 14:00:00 - 2025-12-08 14:00:00 (UTC). Adjust based on your local timezone.

Troubleshooting​

Agent not starting​

Verify the agent JAR exists:

ls -lh /path/to/opentelemetry-javaagent.jar

Check Java version compatibility (requires Java 8+):

java -version

Look for agent startup log message: When your application starts, you should see:

[otel.javaagent] OpenTelemetry Javaagent v2.22.0 started

No metrics appearing in HyperDX​

Verify ClickStack is running and accessible:

docker ps | grep clickstack
curl -v http://localhost:4318/v1/metrics

Check that metrics exporter is configured:

# If using environment variables, verify:
echo $OTEL_METRICS_EXPORTER
# Should output: otlp

Check application logs for OpenTelemetry errors: Look for any error messages related to OpenTelemetry or OTLP export failures in your application logs.

Verify network connectivity: If ClickStack is on a remote host, ensure port 4318 is accessible from your application server.

Verify agent version: Ensure you're using the latest stable agent version (currently 2.22.0), as newer versions often include performance improvements.

Next steps​

Now that you have JVM metrics flowing into ClickStack, consider:

Going to production​

This guide demonstrates configuring the OpenTelemetry Java agent for local testing. For production deployments, include the agent JAR in your container images and configure via environment variables for easier management. For larger environments with many JVM instances, deploy a centralized OpenTelemetry Collector to batch and forward metrics from multiple applications instead of sending directly to ClickStack.

See Ingesting with OpenTelemetry for production deployment patterns and collector configuration examples.