Installation

Add FrcCatalyst to your WPILib robot project.

Table of contents

1. Prerequisites
2. Source candidate and published dependency
3. Option 1: Vendordep (Recommended)
4. Option 2: JitPack (build.gradle)
5. Option 3: Local Maven (From Source)
6. Required: two JVM flags
7. Verify Installation
8. Next Steps
9. RC1 release gates

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Prerequisites

• WPILib 2027 alpha installed (download). Catalyst 2.x targets 2027.0.0-alpha-7; the 2027 toolchain ships Java 25, and Gradle 9.7 or later is required to read it. Gradle 8.x fails with Unsupported class file major version 69.
• A Limelight Systemcore running the matching OS beta. The library and the OS are versioned together — see Systemcore & WPILib 2027 before flashing anything.
• A GradleRIO robot project (created via the WPILib project generator).

• Vendordeps: CTRE Phoenix 6 26.70.0-alpha-2 or later — the first Phoenix build for WPILib alpha-7, published 2026-09-18. RC1 source pins PathPlanner 2027.0.0-alpha-4.1 as an optional compile-time dependency and LimelightLib 2.0.0-beta9-alpha7.

  CTRE devices need 26.70.x firmware. Phoenix 6 26.70.0-alpha-2 is the first Phoenix build for WPILib alpha-7, but it requires 26.70.x device firmware — every TalonFX, CANcoder and Pigeon has to be re-flashed before it will talk to this line, which makes moving a robot here an afternoon’s work, not a git checkout. See Versions and compatibility.

  PathPlanner is optional. RC1 source includes the WPILib Commands v2 bridge needed by PathPlanner while Catalyst uses Commands v3. PathPlanner itself remains compileOnly, so a consumer that uses it must supply its matching vendordep/repository. This is a source dependency statement, not a claim that autonomous behavior has been qualified on hardware. Verify downloaded vendor JSON targets the intended 2027 version before building.

  PhotonVision is not used. There is no 2027 build, and Catalyst is Limelight-first on Systemcore — the pipeline is built into the hardware. If you had it installed for Catalyst 1.x, remove it.

Source candidate and published dependency

Published prerelease: 2.0.0-rc.1 (tag v2.0.0-rc.1).

The RC1 JitPack POM, binary jar, sources and Javadoc were verified before the published vendordep moved from beta.2. Install the release below or build the exact tag from source. The GitHub prerelease contains downloadable artifacts and checksums. This is a Java 25/WPILib 2027 alpha-7 Systemcore prerelease, with hardware qualification still required.

Option 1: Vendordep (Recommended)

The easiest install. In WPILib VS Code, open the command palette and run WPILib: Manage Vendor Libraries → Install new libraries (online), then paste:

https://tomas-1226.github.io/FrcCatalyst/beta/vendordep/FrcCatalyst.json

That adds FrcCatalyst to your project and lets WPILib check for updates. Match Phoenix 6 and LimelightLib to the chosen Catalyst build; PathPlanner is optional. The RC1 dependency uses the compatibility pins listed above. PhotonVision is not part of this build. Optional PathPlanner users must add its matching vendor dependency.

Option 2: JitPack (build.gradle)

If you’d rather add it by hand, put the JitPack repository and the dependency in your robot project’s build.gradle:

repositories {
    // ... your existing repositories ...
    maven { url "https://jitpack.io" }
}

dependencies {
    // ... your existing dependencies ...
    implementation "com.github.TomAs-1226:FrcCatalyst:v2.0.0-rc.1"
}

Option 3: Local Maven (From Source)

If you prefer to build from source or need to modify the library:

# Clone FrcCatalyst
git clone https://github.com/TomAs-1226/FrcCatalyst.git
cd FrcCatalyst
git checkout v2.0.0-rc.1
# Record and review the exact commit before building.
git rev-parse HEAD

# Test the library/example before publishing only to this machine.
./gradlew build publishToMavenLocal

The local Maven example below names the source candidate. Publishing to local Maven does not publish a release remotely. An included Gradle build can avoid local Maven publication entirely.

Then in your robot project’s build.gradle:

repositories {
    mavenLocal()
}

dependencies {
    implementation "com.frccatalyst:FrcCatalyst:2.0.0-rc.1"
}

Required: two JVM flags

Add these to your robot program’s launch arguments. Without them the robot boots, the dashboard connects, and the first command scheduled throws ExceptionInInitializerError from inside WPILib — naming no class of yours, at whatever moment a driver first pressed a button.

--add-opens java.base/jdk.internal.vm=ALL-UNNAMED
--add-opens java.base/java.lang=ALL-UNNAMED

In build.gradle:

frc {
    jvmArgs.addAll([
        "--add-opens", "java.base/jdk.internal.vm=ALL-UNNAMED",
        "--add-opens", "java.base/java.lang=ALL-UNNAMED",
    ])
}

Both are needed, and the second only appears once the first is fixed. jdk.internal.vm gets the command scheduler constructed; java.lang gets a command scheduled. Add one, deploy, and you meet the other on the field.

Commands v3 runs on JDK continuations, which live in jdk.internal.vm and are reached by reflection — hence the flags. Catalyst checks for both when it builds a command and throws something legible if either is missing, so you find out at the line that built the command rather than several seconds later. To ask directly:

CommandRuntime.isAvailable();   // false means the flags are missing

Verify Installation

Create a simple test in your RobotContainer to confirm everything is working:

import frc.lib.catalyst.hardware.MotorType;
import frc.lib.catalyst.util.CatalystMath;

// In your RobotContainer constructor:
System.out.println("Kraken X60 free speed: "
    + MotorType.KRAKEN_X60.freeSpeedRPS() + " RPS");
System.out.println("Processed joystick: "
    + CatalystMath.processJoystick(0.5, 0.05, 2.0, 1.0));

If it compiles and prints the values, you’re good to go!

Next Steps

Head to the Quick Start guide to build your first mechanism in under 5 minutes.

RC1 release gates

This preparation is for Systemcore OS beta 14 / WPILib alpha-7 / Java 25, not a roboRIO 2026 drop-in. Preserve the two runtime --add-opens flags documented in the Systemcore guide. Device firmware must match the documented 26.70.x line.

Before announcing RC1 as installable, require a clean full build for its exact commit, passing regressions, an example/consumer install check against the final artifact, and a verified Maven POM. The downstream Numbers shooting simulation failure was diagnosed and repaired in an isolated team-repository fixture and simulation model; see the 17 October validation evidence. That patch does not change the published RC1 binary or qualify hardware. Keep optional control/observer features at their documented defaults. ARES 1.1 denotes the current multicamera scope; the ARES 2.0 ROS 2-style prototype is deferred. No tag, public release, deployed robot package or firmware change follows from this source guide.