Neo4j Driver Java Skill

When to Use

• Java/Kotlin code connecting to Neo4j (Aura or self-managed)
• Setting up driver, sessions, transactions in Maven/Gradle projects
• Debugging result handling, error recovery, connection pool issues
• Async (CompletableFuture) or reactive (Project Reactor / RxJava) Neo4j access

When NOT to Use

• Cypher query authoring/optimization → neo4j-cypher-skill
• Driver version upgrades → neo4j-migration-skill
• Spring Data Neo4j (@Node, @Relationship, Neo4jRepository) → neo4j-spring-data-skill

Dependency

Maven

<dependency>
    <groupId>org.neo4j.driver</groupId>
    <artifactId>neo4j-java-driver</artifactId>
    <version>6.2.1</version>
</dependency>

Gradle

implementation 'org.neo4j.driver:neo4j-java-driver:6.2.1'

Check latest: https://central.sonatype.com/artifact/org.neo4j.driver/neo4j-java-driver

6.2.0 [2026-06]: Neo4j UUID type + Bolt 6.1 support; QueryProfile in result summary. 6.2.1 [2026-08]: fixes Value#asObject() on UUID values — required if reading UUID properties generically. Neo4j 2026.08 server bundles 6.2.1; 2026.07 bundles 6.2.0.

Server-side UUID type and uuid() constructors ship in Neo4j 2026.08 — use driver >= 6.2.1 against those servers.

Environment Variables

Standard pattern for connection config — never hardcode credentials:

String uri      = System.getenv().getOrDefault("NEO4J_URI",      "neo4j://localhost:7687");
String user     = System.getenv().getOrDefault("NEO4J_USERNAME",  "neo4j");
String password = System.getenv().getOrDefault("NEO4J_PASSWORD",  "");
String database = System.getenv().getOrDefault("NEO4J_DATABASE",  "neo4j");

Spring Boot: inject via @Value("${spring.neo4j.uri}") or application.properties:

spring.neo4j.uri=neo4j+s://xxx.databases.neo4j.io
spring.neo4j.authentication.username=neo4j
spring.neo4j.authentication.password=secret

Driver Lifecycle

One Driver per application — thread-safe, expensive to create. Implement AutoCloseable or use try-with-resources.

// Long-lived singleton
var driver = GraphDatabase.driver(
    "neo4j+s://xxx.databases.neo4j.io",          // Aura TLS+routing
    AuthTokens.basic(user, password));
driver.verifyConnectivity();                      // fail fast

// Short-lived (tests / CLI)
try (var driver = GraphDatabase.driver(uri, AuthTokens.basic(user, password))) {
    driver.verifyConnectivity();
    // ...
}

URI schemes:

Auth options: AuthTokens.basic(u,p) · AuthTokens.bearer(token) · AuthTokens.kerberos(b64) · AuthTokens.none()

Choosing the Right API

CALL { … } IN TRANSACTIONS and USING PERIODIC COMMIT self-manage their transaction — use session.run() only. executableQuery and executeRead/Write will fail for these queries.

session.run() retry [6.1+]: single immediate retry on idempotent errors only (enabled by default). Disable per driver or per session:

// Driver-level — disable for all sessions
var config = Config.builder().withAutoCommitRetriesDisabled(true).build();

// Session-level — overrides driver
var sessionConfig = SessionConfig.builder()
    .withAutoCommitRetriesMode(AutoCommitRetriesMode.DISABLED)  // DEFAULT = follow driver
    .build();

executableQuery — Default

// Read — route to replicas
var result = driver.executableQuery("""
        MATCH (p:Person {name: $name})-[:KNOWS]->(friend)
        RETURN friend.name AS name
        """)
    .withParameters(Map.of("name", "Alice"))
    .withConfig(QueryConfig.builder()
        .withDatabase("neo4j")            // always specify — avoids home-db round-trip
        .withRouting(RoutingControl.READ)
        .build())
    .execute();

result.records().forEach(r -> System.out.println(r.get("name").asString()));
long ms = result.summary().resultAvailableAfter(TimeUnit.MILLISECONDS);

// Write
driver.executableQuery("CREATE (p:Person {name: $name, age: $age})")
    .withParameters(Map.of("name", "Bob", "age", 30))
    .withConfig(QueryConfig.builder().withDatabase("neo4j").build())
    .execute();

Never string-interpolate Cypher. Always .withParameters(Map.of(...)).

Managed Transactions (executeRead / executeWrite)

Sessions are NOT thread-safe — one per request/thread, always close.

try (var session = driver.session(SessionConfig.builder()
        .withDatabase("neo4j").build())) {

    // Read → replica routing
    var names = session.executeRead(tx -> {
        var result = tx.run(
            "MATCH (p:Person) WHERE p.name STARTS WITH $prefix RETURN p.name AS name",
            Map.of("prefix", "Al"));
        return result.stream().map(r -> r.get("name").asString()).toList(); // collect INSIDE
    });

    // Write → leader routing
    session.executeWriteWithoutResult(tx ->
        tx.run("CREATE (p:Person {name: $name})", Map.of("name", "Carol"))
    );
}

Result must be consumed INSIDE the callback

Result is a lazy cursor tied to the open transaction. Transaction closes when callback returns — any read after that throws ResultConsumedException.

// ❌ Returns Result — already closed by the time caller uses it
var result = session.executeRead(tx ->
    tx.run("MATCH (p:Person) RETURN p.name AS name"));
result.stream().forEach(...); // throws ResultConsumedException

// ✅ Collect to List inside callback
var names = session.executeRead(tx ->
    tx.run("MATCH (p:Person) RETURN p.name AS name")
      .stream().map(r -> r.get("name").asString()).toList());

Callback rules

• Consume each Result before next tx.run() — multiple open cursors = undefined behaviour.
• No side effects (HTTP, email, metric increments) — callback may be retried on transient errors.
• Use MERGE (idempotent), not CREATE, for retry-safe writes.
• executeRead → replica; executeWrite → leader.

TransactionConfig — timeouts & metadata

var config = TransactionConfig.builder()
    .withTimeout(Duration.ofSeconds(5))
    .withMetadata(Map.of("app", "myService", "user", userId))  // visible in SHOW TRANSACTIONS
    .build();
session.executeRead(tx -> { /* ... */ }, config);

Explicit Transactions

Use when work spans multiple methods or requires external coordination. Not auto-retried.

try (var session = driver.session(SessionConfig.builder().withDatabase("neo4j").build())) {
    var tx = session.beginTransaction();
    try {
        doPartA(tx);
        doPartB(tx);
        tx.commit();
    } catch (Exception e) {
        try { tx.rollback(); } catch (Exception rb) { e.addSuppressed(rb); }
        throw e;
    }
}

tx.rollback() is a network call — wrap in its own try/catch and use addSuppressed so the original exception is not lost.

Commit uncertainty: if tx.commit() throws ServiceUnavailableException, the commit may or may not have succeeded. Design writes as idempotent (MERGE + unique constraints) so retrying is safe.

Choose explicit vs managed:

• Auto-retry needed → executeRead / executeWrite
• Work spans multiple methods → explicit (pass tx as parameter)
• Coordinating with external I/O → explicit (commit only after I/O succeeds)