U.S. CSL API in Java: screening and error handling

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What this Java integration does

The U.S. Consolidated Screening List combines several export-related screening sources. Its component lists have different purposes and implications. A CSL result should not be presented as a uniform OFAC designation.

The client submits a subject, validates the response, and prints only the screening ID, status, and candidate count. It does not approve a customer, resolve an identity, or make a legal decision. A nonzero exit leaves the local operation incomplete.

Prepare the runtime and a synthetic request

Use Java 21 and Maven. Save the client as src/main/java/Screen.java and the pom.xml shown below at the project root. The example uses the JDK HTTP client and Jackson 2.x for JSON tree validation.

Save the following as request.json. Mira Calder is an invented subject and sandbox@1 uses synthetic fixtures, not a current production sanctions search. Set SANCTIONSKIT_API_KEY to your test key in the process environment. Set SCREENING_OPERATION_ID to a new persistent identifier for this operation, and reuse it only for an unchanged retry.

{
  "subject": {
    "name": "Mira Calder",
    "entityType": "person",
    "birthDate": "1984"
  },
  "package": "sandbox@1",
  "retention": "standard"
}

Add the project configuration

Save this as pom.xml. These dependencies are for the standalone tutorial, not dependencies to add to SanctionsKit’s website build. Review and lock them under your own maintenance process.

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion><groupId>example</groupId><artifactId>sanctions-screen</artifactId><version>1.0.0</version>
  <properties><maven.compiler.release>21</maven.compiler.release><project.build.sourceEncoding>UTF-8</project.build.sourceEncoding></properties>
  <dependencies><dependency><groupId>com.fasterxml.jackson.core</groupId><artifactId>jackson-databind</artifactId><version>2.18.10</version></dependency></dependencies>
  <build><plugins>
    <plugin><groupId>org.apache.maven.plugins</groupId><artifactId>maven-compiler-plugin</artifactId><version>3.13.0</version></plugin>
    <plugin><groupId>org.codehaus.mojo</groupId><artifactId>exec-maven-plugin</artifactId><version>3.5.0</version><configuration><mainClass>Screen</mainClass></configuration></plugin>
  </plugins></build>
</project>

Send the request and validate the result

Save the client as src/main/java/Screen.java. The endpoint is fixed to SanctionsKit’s HTTPS API. The example rejects redirects, requires explicit authorization before using a live key, and does not retry automatically. Production integrations should preserve the operation state before the first network call.

// Java 21+, Jackson 2.x. Backend or trusted CLI. See the adjacent pom.xml.
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;
import java.nio.file.Files;
import java.nio.file.Path;
import java.time.Duration;
import java.util.Map;
import java.util.concurrent.TimeUnit;

public final class Screen {
    public static void main(String[] args) {
        try { run(args); }
        catch (Exception error) {
            // Parser exceptions may contain excerpts, so do not print their messages.
            System.err.println("Screening incomplete. Check the operation before retrying.");
            System.exit(1);
        }
    }
    static void run(String[] args) throws Exception {
        String key = System.getenv("SANCTIONSKIT_API_KEY");
        String operation = System.getenv("SCREENING_OPERATION_ID");
        if (key == null || operation == null || operation.isBlank()) throw new IllegalArgumentException("Missing configuration");
        if (!key.startsWith("sk_test_") && !(key.startsWith("sk_live_") && "yes".equals(System.getenv("ALLOW_LIVE_SCREENING")))) {
            throw new IllegalArgumentException("Live operation not explicitly authorized");
        }
        byte[] raw = Files.readAllBytes(Path.of(args.length > 0 ? args[0] : "../request.sandbox.json"));
        if (raw.length > 65536) throw new IllegalArgumentException("Oversized request");
        ObjectMapper mapper = new ObjectMapper();
        JsonNode body = mapper.readTree(raw);
        if (body == null || !body.isObject() || !body.has("subject") || body.has("sources") == body.has("package")) {
            throw new IllegalArgumentException("Invalid request object");
        }
        HttpRequest request = HttpRequest.newBuilder(URI.create("https://www.sanctionskit.com/api/v1/screenings"))
            .timeout(Duration.ofSeconds(25))
            .header("Authorization", "Bearer " + key).header("Content-Type", "application/json")
            .header("Idempotency-Key", operation).POST(HttpRequest.BodyPublishers.ofByteArray(raw)).build();
        try (HttpClient client = HttpClient.newBuilder().connectTimeout(Duration.ofSeconds(10))
                .followRedirects(HttpClient.Redirect.NEVER).build()) {
            // A file subscriber avoids buffering the complete body in memory.
            Path temp = Files.createTempFile("sanctions-response-", ".json");
            try {
                var future = client.sendAsync(request, HttpResponse.BodyHandlers.ofFile(temp));
                HttpResponse<Path> response;
                try { response = future.get(30, TimeUnit.SECONDS); }
                catch (Exception error) { future.cancel(true); throw error; }
                if (response.statusCode() < 200 || response.statusCode() >= 300 || Files.size(temp) > 8 * 1024 * 1024) {
                    throw new IllegalStateException("Incomplete HTTP response");
                }
                JsonNode envelope = mapper.readTree(temp.toFile());
                JsonNode data = envelope == null ? null : envelope.get("data");
                if (data == null || !data.isObject() || !data.path("id").isTextual() || data.path("id").asText().isEmpty()
                        || !data.path("status").isTextual() || !data.path("matches").isArray()) {
                    throw new IllegalStateException("Unexpected screening response");
                }
                String status = data.get("status").asText(); int count = data.get("matches").size();
                if (!(status.equals("potential_match") || status.equals("no_match"))
                        || (status.equals("no_match") && count != 0) || (status.equals("potential_match") && count == 0)) {
                    throw new IllegalStateException("Inconsistent screening response");
                }
                System.out.println(mapper.writeValueAsString(Map.of("id", data.get("id").asText(), "status", status, "candidateCount", count)));
            } finally { Files.deleteIfExists(temp); }
        }
    }
}

Run the client

Run this from the directory containing request.json and the project files. Keep the API key out of committed files and shell tracing. The tutorial’s request-file limit is 64 KiB and its response parsing limit is 8 MiB; these are client safeguards, not claims about API service limits.

Validate JsonNode types before converting values; a missing field must not become a default empty string or zero. The example rejects redirects and uses a time-bounded asynchronous file download before parsing. The size check bounds parsing input, not a complete production temporary-storage quota.

mvn compile exec:java -Dexec.args="request.json"

Change to the required production coverage

The documented SanctionsKit identifier is us-csl. Confirm the current coverage and preserve each returned record’s underlying list identity. Separate-source overlap can occur when a portfolio also selects other U.S. lists; retain provenance rather than silently merging the evidence.

For an authorized production operation, replace the package field with the sources array shown below, supply the actual lawfully held subject details, use a live key, and set ALLOW_LIVE_SCREENING=yes. Keep the complete request in request.json and create a new operation ID. Do not send both sources and package. The fragment below is a coverage change, not a complete request.

{
  "sources": [
    "us-csl"
  ]
}

Preserve the source details a reviewer needs

Keep the component authority, list identity, record reference, and restriction context available to the trade reviewer. Screening a party does not classify goods, determine end use, establish a license requirement, or replace a broader export-control assessment.

Retain the screening ID with your internal subject reference. Retrieve the complete evidence through the documented retained-result workflow when authorized; the console summary deliberately does not print raw identity details. A later analyst decision must not overwrite the original screening outcome.

Handle failures and test the source-specific edge cases

Treat HTTP errors, timeouts, malformed JSON, missing fields, unknown statuses, and unavailable required coverage as incomplete checks. A 401 or 403 needs credential or scope correction. A 409 needs idempotency-conflict handling. A 429 needs its specific rate-limit or usage-cap treatment; it is not a no-match result.

Test organization subjects and candidates from different component lists. Confirm that the application does not transform every CSL candidate into an SDN finding, and that it can retain separate records with similar names from different authorities.

Use a mock HTTP server to exercise malformed JSON, absent data, non-text statuses, and a non-array matches field. Pin and review dependencies in your project rather than automatically updating Jackson without compatibility tests.

Verify both valid result states and inconsistent status/matches combinations.
Retry an accepted operation only with its original key and unchanged payload.
Keep missing identity facts unknown instead of inventing contradictory values.
Route potential matches into review before the separate business decision.
Keep secrets, submitted names, and raw error bodies out of routine logs.