DEV Community

Said Olano
Said Olano

Posted on

Apache Derby: A Lightweight Java-Based Relational Database (2026-08-29 17:30)

#apachederby #java #database #embeddeddatabase

Apache Derby: A Lightweight Java-Based Relational Database

Apache Derby is a full-featured, open-source relational database management system (RDBMS) implemented entirely in Java. Small in footprint yet standards-compliant, it's an excellent choice for embedded applications, prototyping, and testing environments. This post explores what makes Derby useful and how to get started.

What Is Apache Derby?

Derby is developed and maintained by the Apache Software Foundation. Oracle also distributes it under the name Java DB as part of some JDK builds. It supports the SQL standard, JDBC, and Java stored procedures, all while occupying roughly 3.5 MB for the base engine.

Key characteristics include:

  • Pure Java implementation — runs anywhere a JVM runs.
  • Small footprint — ideal for embedding directly inside applications.
  • Standards-based — supports SQL, JDBC, and Java EE.
  • Zero administration — no complex setup or DBA required.

Deployment Modes

Derby supports two primary deployment modes.

1. Embedded Mode

The database engine runs in the same JVM as your application. There is no separate server process, making it perfect for desktop apps and unit tests.

// Embedded connection URL
String url = "jdbc:derby:myDB;create=true";
Connection conn = DriverManager.getConnection(url);
Enter fullscreen mode Exit fullscreen mode

2. Client/Server Mode

Derby runs as a network server (using the Derby Network Server), allowing multiple clients to connect over TCP/IP.

// Client/server connection URL
String url = "jdbc:derby://localhost:1527/myDB;create=true";
Connection conn = DriverManager.getConnection(url);
Enter fullscreen mode Exit fullscreen mode

Getting Started

Adding the Dependency

For a Maven project, include the appropriate artifact.

<dependency>
    <groupId>org.apache.derby</groupId>
    <artifactId>derby</artifactId>
    <version>10.17.1.0</version>
</dependency>
Enter fullscreen mode Exit fullscreen mode

Note: From Derby 10.15 onward, the driver class is org.apache.derby.jdbc.EmbeddedDriver. Modern JDBC uses auto-loading via the service provider mechanism, so explicit class loading is usually unnecessary.

Creating a Table and Inserting Data 

import java.sql.*;

public class DerbyExample {
    public static void main(String[] args) throws SQLException {
        String url = "jdbc:derby:sampleDB;create=true";

        try (Connection conn = DriverManager.getConnection(url);
             Statement stmt = conn.createStatement()) {

            // Create a table
            stmt.execute("CREATE TABLE employees (" +
                         "id INT PRIMARY KEY, " +
                         "name VARCHAR(100), " +
                         "salary DECIMAL(10,2))");

            // Insert a row
            stmt.executeUpdate(
                "INSERT INTO employees VALUES (1, 'Alice', 75000.00)");

            // Query the data
            ResultSet rs = stmt.executeQuery(
                "SELECT * FROM employees");
            while (rs.next()) {
                System.out.printf("%d - %s - %.2f%n",
                    rs.getInt("id"),
                    rs.getString("name"),
                    rs.getDouble("salary"));
            }
        }
    }
}
Enter fullscreen mode Exit fullscreen mode

Shutting Down Cleanly

In embedded mode, shutting down Derby properly flushes data and releases file locks.

try {
    DriverManager.getConnection("jdbc:derby:;shutdown=true");
} catch (SQLException e) {
    // Derby throws SQLState XJ015 on successful shutdown — this is expected
    if (!"XJ015".equals(e.getSQLState())) {
        throw e;
    }
}
Enter fullscreen mode Exit fullscreen mode

Common Use Cases

Use Case Why Derby Fits
Unit and integration testing Fast, in-memory or file-based, no external server
Desktop applications Embedded engine ships with the app
Prototyping Zero configuration and quick setup
Learning SQL/JDBC Lightweight and easy to reset

In-Memory Databases

For tests, Derby can run entirely in memory, discarding data when the JVM stops.

String url = "jdbc:derby:memory:testDB;create=true";
Enter fullscreen mode Exit fullscreen mode

Advantages and Limitations

Advantages:

  • Trivial to embed and distribute.
  • No installation or administration overhead.
  • Strong SQL standard compliance.
  • Portable across platforms.

Limitations:

  • Not designed for very large datasets or heavy concurrency.
  • Fewer advanced features than PostgreSQL or Oracle.
  • Performance under high load lags behind dedicated servers.

Conclusion

Apache Derby fills an important niche in the Java ecosystem: a compact, standards-compliant database that requires virtually no setup. While it isn't intended to replace enterprise-grade servers for large production workloads, it excels in embedded scenarios, automated testing, and rapid prototyping. If your application needs a self-contained SQL database without operational overhead, Derby is well worth considering.

Top comments (0)