charges-on-payment-intent - Update code that uses the deprecated paymentIntent.getCharges() method (removed in newer API versions). Must use Charge.list() or latestChargeObject instead.
invoice-partial-payments - Update invoice-related code to work with SDK v29.x
subscription-billing-migration - Update subscription-related code to work with SDK v29.x

SDK Versions

Before	After
stripe-java v20.x/v27.x	stripe-java v29.0.0
API 2022-08-01	API 2025-03-31.basil

Prerequisites

JDK 11+
Maven 3.x
Ruby 3.x and Bundler (for the grader)

Local Setup

Each problem lives in environment/<problem>/server/. To run a problem locally:

1. Configure Stripe API Keys

# Pick a problem to work on
PROBLEM=charges-on-payment-intent  # or invoice-partial-payments, subscription-billing-migration

# Create .env from the example
cp environment/$PROBLEM/server/.env.example environment/$PROBLEM/server/.env

Edit environment/$PROBLEM/server/.env and fill in your Stripe test keys:

STRIPE_SECRET_KEY=sk_test_...
STRIPE_PUBLISHABLE_KEY=pk_test_...

2. Build and Run the Server

cd environment/$PROBLEM/server
mvn install -DskipTests
mvn exec:java -Dexec.mainClass="com.stripe.sample.Server"

The server starts on http://localhost:4242. Verify it's running:

curl http://localhost:4242/config

3. Run the Grader (should fail on the initial environment)

In a separate terminal, from the sdk-upgrades-java/ root:

# Copy .env so the grader can access Stripe API keys
cp environment/$PROBLEM/server/.env grader/.env

# Install grader dependencies (first time only)
cd grader
bundle install

# Run the grader RSpec tests directly against the running server
bundle exec rspec $PROBLEM/grade.rb --format documentation

Docker Setup (run_solution.sh)

The Docker workflow tests both the unmodified environment (should fail) and the reference solution (should pass) automatically.

Option A: Using a .env file (preferred)

Create a .env file in the sdk-upgrades-java/ root directory:

cat > .env << 'EOF'
STRIPE_SECRET_KEY=sk_test_...
STRIPE_PUBLISHABLE_KEY=pk_test_...
EOF

Then run:

./run_solution.sh

Option B: Using environment variables

export STRIPE_SECRET_KEY=sk_test_...
./run_solution.sh

The Docker container will:

Build and start each problem's server with the old SDK (environment) and run the grader -- expects failure
Build and start each problem's server with the new SDK (solution) and run the grader -- expects pass

Structure

sdk-upgrades-java/
├── environment/          # Given to AI (old SDK code)
│   ├── charges-on-payment-intent/
│   ├── invoice-partial-payments/
│   └── subscription-billing-migration/
├── grader/               # Hidden (RSpec tests)
├── solution/             # Reference (upgraded SDK code)
├── Dockerfile
├── run_inside_docker.sh
└── run_solution.sh

Grading

Each problem's grader:

Validates Stripe SDK version is 29.x (fails immediately if not)
Starts the Java server on port 4242
Runs RSpec tests against HTTP endpoints
Returns pass/fail based on response correctness

Leak Detection

UUIDs are embedded in grader/solution files to detect leaks:

charges-on-payment-intent (UUID 284c2a9a-b3ea-4767-b334-7d8b18535229):

Grader: sdk-upgrades-java-charges-on-payment-intent-284c2a9a-b3ea-4767-b334-7d8b18535229-grader
Solution: sdk-upgrades-java-charges-on-payment-intent-284c2a9a-b3ea-4767-b334-7d8b18535229-solution

invoice-partial-payments (UUID 7c08d1f4-962c-4f27-b31f-4edd6a5149bc):

Grader: sdk-upgrades-java-invoice-partial-payments-7c08d1f4-962c-4f27-b31f-4edd6a5149bc-grader
Solution: sdk-upgrades-java-invoice-partial-payments-7c08d1f4-962c-4f27-b31f-4edd6a5149bc-solution

subscription-billing-migration (UUID f73c1831-b6af-4f3a-b1ad-e957b12027e6):

Grader: sdk-upgrades-java-subscription-billing-migration-f73c1831-b6af-4f3a-b1ad-e957b12027e6-grader
Solution: sdk-upgrades-java-subscription-billing-migration-f73c1831-b6af-4f3a-b1ad-e957b12027e6-solution