# Configuring Blackfire Continuous Profiler for Java

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[configuring continuous profiling](https://www.youtube-nocookie.com/embed/1q_E6fk2Q1Q?rel=0&showinfo=0&modestbranding=1&autoplay=0)

The Java continuous profiling is currently made across 3 dimensions:

- **CPU Time**: Time spent running on the CPU
- **Wall-time**: elapsed time per function call
- **Allocations**: Number of objects allocated

## Requirements

- Java >= 17
- [Blackfire Agent](../up-and-running/configuration/agent) >= 2.13.0

## Installation

1. Download the latest ddprof Java release:

    ```bash
    wget -O dd-java-agent.jar 'https://dtdg.co/latest-java-tracer'
    ```

    Alternatively, add the following to your `Dockerfile` if you are using Docker:

    ```bash
    ADD 'https://dtdg.co/latest-java-tracer' dd-java-agent.jar
    ```

    > **Note**
    >
    > Blackfire utilizes the open source Datadog profiler to collect continuous profiling traces and, via its [agent](../reference-guide/glossary#term-agent), sends it directly to Blackfire's ingesters where we process and analyze the data for your observability needs.
2. Update your Java application start command:

    ```bash
    java \
       -javaagent:dd-java-agent.jar \
       -jar <YOUR_SERVICE>.jar <YOUR_SERVICE_FLAGS>
    ```
3. Enable the Java Continuous Profiler by defining these environment variables:

    - `DD_PROFILING_ENABLED=true`: controls the activation of the continuous profiler.
    - `DD_PROFILING_DDPROF_ENABLED=false`: disables native profiling
    - `DD_INSTRUMENTATION_TELEMETRY_ENABLED=false`: disables internal telemetry
    - `DD_TRACE_ENABLED=false`: disable tracing
    - `DD_SERVICE=my-java-app`: sets the application name.
    - `DD_TRACE_AGENT_URL=unix:///var/run/blackfire/agent.sock`: has Blackfire Agent collect traces.
    - `DD_PROFILING_ALLOCATION_ENABLED=true`: enables allocation profiling
    - `DD_PROFILING_ENABLED_EVENTS="jdk.ObjectAllocationInNewTLAB,jdk.ObjectAllocationOutsideTLAB"`: enables Object allocation

There is also some additional configuration that can be done using environment variables:

- `BLACKFIRE_LOG_FILE`: Sets the log file. The default is logging to `stderr`.
- `BLACKFIRE_LOG_LEVEL`: Sets the log level. The default is logging only errors.