feat: add CDP payments Java scripts

.env.example

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+# Preferred: path to the JSON file downloaded from the CDP Portal.
+CDP_API_KEY_FILE=/absolute/path/to/cdp_api_key.json
+
+# Alternative to CDP_API_KEY_FILE.
+# CDP_KEY_ID=organizations/.../apiKeys/...
+# CDP_KEY_SECRET=base64-ed25519-secret-or-ecdsa-pem
+
+# Defaults to sandbox. Supported values: sandbox, production.
+CDP_ENVIRONMENT=sandbox
+
+# Optional custom endpoint, primarily for local testing.
+# CDP_API_BASE_URL=https://sandbox.cdp.coinbase.com/platform

.github/workflows/ci.yml

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+name: CI
+
+on:
+  pull_request:
+  push:
+    branches: [main]
+
+permissions:
+  contents: read
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-java@v4
+        with:
+          distribution: temurin
+          java-version: "17"
+          cache: maven
+      - run: make lint
+      - run: make test
+      - run: make build

.gitignore

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+target/
+.idea/
+.vscode/
+*.iml
+.DS_Store
+.env
+cdp_api_key.json
+*.pem

LICENSE

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Makefile

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+.PHONY: build test lint format clean run
+
+build:
+	mvn -q -DskipTests package
+
+test:
+	mvn -q test
+
+lint:
+	mvn -q spotless:check
+
+format:
+	mvn -q spotless:apply
+
+clean:
+	mvn -q clean
+
+run:
+	@test -n "$(SCRIPT)" || (echo "Usage: make run SCRIPT=accounts.ListAccounts ARGS='...'" >&2; exit 2)
+	mvn -q compile exec:java \
+		-Dexec.mainClass=com.coinbase.cdp.scripts.$(SCRIPT) \
+		-Dexec.args="$(ARGS)"

README.md

@@ -1 +1,111 @@
-# CDP Payments Java Scripts
+# CDP Payments Java scripts
+
+Runnable Java examples for the [CDP Payments and Custodial Accounts APIs](https://docs.cdp.coinbase.com/api-reference/v2/introduction). Each API operation has one `main` class. Scripts call the REST API directly, print formatted responses, and default to CDP Sandbox.
+
+## Requirements
+
+- JDK 17 or newer
+- Maven 3.9 or newer
+- A Sandbox API key with the permissions required by the endpoint
+
+Create and fund a simulated account using the [Custodial Wallets quickstart](https://docs.cdp.coinbase.com/wallets/custodial-wallets/quickstart). Sandbox never moves real funds.
+
+## Configure credentials
+
+Keep credentials outside this repository. Point to the JSON file downloaded from the CDP Portal:
+
+```bash
+export CDP_API_KEY_FILE="$HOME/Downloads/cdp_api_key.json"
+```
+
+You can instead export its values directly:
+
+```bash
+export CDP_KEY_ID='organizations/.../apiKeys/...'
+export CDP_KEY_SECRET='base64 Ed25519 secret or ECDSA PEM'
+```
+
+`CDP_API_KEY_FILE` takes precedence. Both recommended Ed25519 keys and legacy ECDSA keys are supported.
+
+Scripts use `https://sandbox.cdp.coinbase.com/platform` unless configured otherwise:
+
+```bash
+export CDP_ENVIRONMENT=production
+# Or, for a custom server:
+export CDP_API_BASE_URL=https://example.test/platform
+```
+
+## Run scripts
+
+Build and see a script's options:
+
+```bash
+make build
+make run SCRIPT=accounts.ListAccounts ARGS='--help'
+```
+
+List accounts and balances:
+
+```bash
+make run SCRIPT=accounts.ListAccounts
+make run SCRIPT=accounts.ListBalances ARGS='--account-id account_123'
+```
+
+Create an account from a sample request:
+
+```bash
+make run SCRIPT=accounts.CreateAccount \
+  ARGS='--body-file examples/requests/create-account.json'
+```
+
+Create a Sandbox transfer after replacing `account_REPLACE_ME` in the sample:
+
+```bash
+make run SCRIPT=transfers.CreateTransfer \
+  ARGS='--body-file examples/requests/create-transfer.json'
+```
+
+Mutating scripts accept `--body '{...}'` or `--body-file path`, never both. Eligible operations also accept `--idempotency-key UUID`. When omitted, the script generates a UUID v4 and prints it to stderr so the request can be retried safely.
+
+Every non-2xx response returns a nonzero exit code. JSON responses are formatted on stdout. Diagnostics and generated idempotency keys go to stderr.
+
+For a runnable Sandbox command for every account, deposit-destination, transfer, and payment-method endpoint, see [`examples/README.md`](examples/README.md).
+
+## Endpoint scripts
+
+| API | Script | Method and path |
+| --- | --- | --- |
+| Accounts | `accounts.ListAccounts` | `GET /v2/accounts` |
+| Accounts | `accounts.CreateAccount` | `POST /v2/accounts` |
+| Accounts | `accounts.GetAccount` | `GET /v2/accounts/{accountId}` |
+| Accounts | `accounts.ListBalances` | `GET /v2/accounts/{accountId}/balances` |
+| Accounts | `accounts.GetBalance` | `GET /v2/accounts/{accountId}/balances/{asset}` |
+| Deposit Destinations | `depositdestinations.ListDepositDestinations` | `GET /v2/deposit-destinations` |
+| Deposit Destinations | `depositdestinations.CreateDepositDestination` | `POST /v2/deposit-destinations` |
+| Deposit Destinations | `depositdestinations.GetDepositDestination` | `GET /v2/deposit-destinations/{depositDestinationId}` |
+| Transfers | `transfers.CreateTransfer` | `POST /v2/transfers` |
+| Transfers | `transfers.ListTransfers` | `GET /v2/transfers` |
+| Transfers | `transfers.GetTransfer` | `GET /v2/transfers/{transferId}` |
+| Transfers | `transfers.ExecuteTransfer` | `POST /v2/transfers/{transferId}/execute` |
+| Transfers | `transfers.SubmitTravelRule` | `POST /v2/transfers/{transferId}/travel-rule` |
+| Payment Methods | `paymentmethods.ListPaymentMethods` | `GET /v2/payment-methods` |
+| Payment Methods | `paymentmethods.GetPaymentMethod` | `GET /v2/payment-methods/{paymentMethodId}` |
+
+Run any script with `--help` for its path and query options. List operations expose every filter and pagination field in the [v2 OpenAPI specification](https://docs.cdp.coinbase.com/api-reference/v2/cdp-api-v2.yaml).
+
+## Development
+
+Use Make targets rather than invoking their underlying tools:
+
+```bash
+make format
+make lint
+make test
+make build
+```
+
+Automated tests use a local HTTP server and do not contact CDP.
+
+## License
+
+Apache License 2.0. See [LICENSE](LICENSE).

SECURITY.md

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+# Security
+
+Never commit CDP API keys, private keys, production identifiers, or customer data. Use environment variables or an external key file.
+
+Report suspected vulnerabilities through Coinbase's [HackerOne program](https://hackerone.com/coinbase). Do not disclose vulnerabilities in a public issue.

THIRD-PARTY-NOTICES

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+This project uses open source libraries distributed under their respective licenses.
+
+- Jackson, Apache License 2.0
+- Nimbus JOSE + JWT, Apache License 2.0
+- Bouncy Castle, MIT License
+- Picocli, Apache License 2.0
+- JUnit, Eclipse Public License 2.0