tessl/maven-com-h2database--h2

H2 Database Engine - A very fast, open source, JDBC API database with embedded and server modes, transaction support, multi-version concurrency, browser-based console application, encrypted databases, fulltext search, and pure Java implementation with small footprint

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JDBC Connectivity

Name: tessl/maven-com-h2database--h2
Author: tessl

H2 provides comprehensive JDBC 4.2 compliant database connectivity with embedded and server deployment modes. It supports standard JDBC APIs along with H2-specific enhancements for connection pooling, XA transactions, and various authentication methods.

Core JDBC Classes

Driver

The main H2 JDBC driver implementation.

public class Driver implements java.sql.Driver, JdbcDriverBackwardsCompat {
    public Connection connect(String url, Properties info) throws SQLException;
    public boolean acceptsURL(String url) throws SQLException;
    public DriverPropertyInfo[] getPropertyInfo(String url, Properties info) throws SQLException;
    public int getMajorVersion();
    public int getMinorVersion();
    public boolean jdbcCompliant();
    
    // H2-specific methods
    public static Driver load();
    public static void unload();
    public static void setDefaultConnection(Connection c);
}

Usage Examples:

// Automatic driver loading (Java 6+)
Connection conn = DriverManager.getConnection("jdbc:h2:mem:test", "sa", "");

// Manual driver registration (older Java versions)
Class.forName("org.h2.Driver");
Connection conn = DriverManager.getConnection("jdbc:h2:mem:test", "sa", "");

// Using Properties
Properties props = new Properties();
props.setProperty("user", "sa");
props.setProperty("password", "mypassword");
props.setProperty("CACHE_SIZE", "32768");
Connection conn = DriverManager.getConnection("jdbc:h2:~/mydb", props);

JdbcDataSource

DataSource implementation supporting connection pooling and JEE integration.

public class JdbcDataSource implements DataSource, XADataSource, 
                                      ConnectionPoolDataSource, 
                                      Serializable, Referenceable {
    // DataSource methods
    public Connection getConnection() throws SQLException;
    public Connection getConnection(String username, String password) throws SQLException;
    
    // Configuration methods
    public void setURL(String url);
    public String getURL();
    public void setUser(String user);
    public String getUser();
    public void setPassword(String password);
    public void setDescription(String description);
    public String getDescription();
    
    // Connection pool methods
    public PooledConnection getPooledConnection() throws SQLException;
    public PooledConnection getPooledConnection(String user, String password) throws SQLException;
    
    // XA methods
    public XAConnection getXAConnection() throws SQLException;
    public XAConnection getXAConnection(String user, String password) throws SQLException;
    
    // Logging
    public void setLogWriter(PrintWriter out);
    public PrintWriter getLogWriter();
    public void setLoginTimeout(int seconds);
    public int getLoginTimeout();
}

Usage Examples:

// Basic DataSource usage
JdbcDataSource ds = new JdbcDataSource();
ds.setURL("jdbc:h2:~/mydb");
ds.setUser("sa");
ds.setPassword("mypassword");
ds.setDescription("My H2 Database");

Connection conn = ds.getConnection();

// In application server context (web.xml or context.xml)
// <Resource name="jdbc/h2db" auth="Container" type="javax.sql.DataSource"
//           factory="org.h2.jdbcx.JdbcDataSourceFactory"
//           url="jdbc:h2:~/mydb" user="sa" password=""/>

// JNDI lookup
Context ctx = new InitialContext();
DataSource ds = (DataSource) ctx.lookup("java:comp/env/jdbc/h2db");
Connection conn = ds.getConnection();

JdbcConnectionPool

Simple connection pool implementation.

public class JdbcConnectionPool implements DataSource {
    public static JdbcConnectionPool create(String url, String user, String password);
    public static JdbcConnectionPool create(DataSource dataSource);
    
    public Connection getConnection() throws SQLException;
    public Connection getConnection(String username, String password) throws SQLException;
    
    // Pool management
    public void setMaxConnections(int max);
    public int getMaxConnections();
    public void setTimeoutMs(int timeoutMs);
    public int getTimeoutMs();
    
    // Pool monitoring
    public int getActiveConnections();
    public void dispose();
}

Usage Examples:

// Create connection pool
JdbcConnectionPool cp = JdbcConnectionPool.create(
    "jdbc:h2:~/mydb", "sa", "mypassword");
cp.setMaxConnections(10);
cp.setTimeoutMs(30000);

// Use pooled connections
Connection conn = cp.getConnection();
try {
    // database operations
} finally {
    conn.close(); // returns connection to pool
}

// Clean up pool
cp.dispose();

JdbcXAConnection

XA (distributed transaction) support.

public class JdbcXAConnection implements XAConnection {
    public XAResource getXAResource() throws SQLException;
    public Connection getConnection() throws SQLException;
    public void close() throws SQLException;
    
    // Event listeners
    public void addConnectionEventListener(ConnectionEventListener listener);
    public void removeConnectionEventListener(ConnectionEventListener listener);
}

Usage Examples:

// XA transaction usage (typically managed by application server)
JdbcDataSource ds = new JdbcDataSource();
ds.setURL("jdbc:h2:~/mydb");
XAConnection xaConn = ds.getXAConnection("sa", "");

XAResource xaRes = xaConn.getXAResource();
Connection conn = xaConn.getConnection();

// XA transaction management
Xid xid = new MyXid();
xaRes.start(xid, XAResource.TMNOFLAGS);
// perform database operations
xaRes.end(xid, XAResource.TMSUCCESS);
xaRes.prepare(xid);
xaRes.commit(xid, false);

Connection URL Formats

H2 supports various connection URL formats for different deployment scenarios:

Embedded Database URLs

// In-memory database (data lost when JVM exits)
"jdbc:h2:mem:dbname"
"jdbc:h2:mem:dbname;DB_CLOSE_DELAY=-1" // keep open until explicitly closed

// File-based database
"jdbc:h2:~/dbname"           // user home directory
"jdbc:h2:./dbname"           // current directory  
"jdbc:h2:/path/to/dbname"    // absolute path
"jdbc:h2:C:/data/dbname"     // Windows path

// Split database files
"jdbc:h2:split:~/dbname"     // split into multiple files

Server Database URLs

// TCP server connection
"jdbc:h2:tcp://localhost/~/dbname"
"jdbc:h2:tcp://server:9092/~/dbname"

// SSL encrypted connection
"jdbc:h2:ssl://localhost/~/dbname"

// Mixed mode (embedded + server)
"jdbc:h2:~/dbname;AUTO_SERVER=TRUE"
"jdbc:h2:~/dbname;AUTO_SERVER=TRUE;AUTO_SERVER_PORT=9090"

Connection Parameters

Common connection parameters can be appended to URLs:

// Authentication
"jdbc:h2:~/db;USER=sa;PASSWORD=mypass"

// Encryption
"jdbc:h2:~/secure;CIPHER=AES"              // AES encryption
"jdbc:h2:~/secure;CIPHER=XTEA"             // XTEA encryption

// Access control
"jdbc:h2:~/db;ACCESS_MODE_DATA=r"          // read-only
"jdbc:h2:~/db;ACCESS_MODE_LOG=r"           // read-only transaction log

// Performance tuning
"jdbc:h2:~/db;CACHE_SIZE=65536"            // cache size in KB
"jdbc:h2:~/db;LOCK_TIMEOUT=10000"          // lock timeout in ms
"jdbc:h2:~/db;WRITE_DELAY=0"               // write delay in ms

// Compatibility
"jdbc:h2:~/db;MODE=MySQL"                  // MySQL compatibility
"jdbc:h2:~/db;MODE=PostgreSQL"             // PostgreSQL compatibility
"jdbc:h2:~/db;MODE=Oracle"                 // Oracle compatibility

// Debugging
"jdbc:h2:~/db;TRACE_LEVEL_FILE=2"          // file trace level
"jdbc:h2:~/db;TRACE_LEVEL_SYSTEM_OUT=2"    // console trace level

Connection Properties

Properties can be set via connection URLs or Properties object:

// Common properties
public static final String USER = "user";
public static final String PASSWORD = "password";
public static final String CACHE_SIZE = "CACHE_SIZE";
public static final String LOCK_TIMEOUT = "LOCK_TIMEOUT";
public static final String WRITE_DELAY = "WRITE_DELAY";
public static final String TRACE_LEVEL_FILE = "TRACE_LEVEL_FILE";
public static final String MODE = "MODE";
public static final String CIPHER = "CIPHER";
public static final String ACCESS_MODE_DATA = "ACCESS_MODE_DATA";
public static final String AUTO_SERVER = "AUTO_SERVER";

Usage Examples:

Properties props = new Properties();
props.setProperty("user", "sa");
props.setProperty("password", "");
props.setProperty("CACHE_SIZE", "32768");
props.setProperty("TRACE_LEVEL_FILE", "2");
props.setProperty("MODE", "PostgreSQL");

Connection conn = DriverManager.getConnection("jdbc:h2:~/mydb", props);

Connection Pooling Best Practices

public class DatabaseManager {
    private static JdbcConnectionPool pool;
    
    static {
        pool = JdbcConnectionPool.create(
            "jdbc:h2:~/production", "sa", "strongpassword");
        pool.setMaxConnections(20);
        pool.setTimeoutMs(30000);
    }
    
    public static Connection getConnection() throws SQLException {
        return pool.getConnection();
    }
    
    public static void shutdown() {
        if (pool != null) {
            pool.dispose();
        }
    }
    
    // Usage pattern
    public void performDatabaseOperation() {
        try (Connection conn = getConnection();
             PreparedStatement stmt = conn.prepareStatement("SELECT * FROM users WHERE id = ?")) {
            
            stmt.setInt(1, 123);
            ResultSet rs = stmt.executeQuery();
            // process results
            
        } catch (SQLException e) {
            // handle exception
            e.printStackTrace();
        }
    }
}

Authentication and Security

// Custom authentication
"jdbc:h2:~/db;AUTHENTICATOR=com.mycompany.MyAuthenticator"

// User to roles mapping
"jdbc:h2:~/db;USER_TO_ROLES_MAPPER=com.mycompany.MyMapper"

// Credential validation
"jdbc:h2:~/db;CREDENTIALS_VALIDATOR=com.mycompany.MyValidator"

// Example custom authenticator
public class MyAuthenticator implements Authenticator {
    @Override
    public boolean authenticate(String userName, String password, String realm) {
        // Custom authentication logic
        return validateUser(userName, password);
    }
}

Error Handling

H2 JDBC operations throw standard SQLException with H2-specific error codes:

try {
    Connection conn = DriverManager.getConnection("jdbc:h2:~/db", "sa", "");
    // database operations
} catch (SQLException e) {
    int errorCode = e.getErrorCode();
    String sqlState = e.getSQLState();
    
    // H2-specific error handling
    switch (errorCode) {
        case ErrorCode.DATABASE_NOT_FOUND_1:
            System.err.println("Database file not found");
            break;
        case ErrorCode.WRONG_USER_OR_PASSWORD:
            System.err.println("Authentication failed");
            break;
        case ErrorCode.TABLE_OR_VIEW_NOT_FOUND_1:
            System.err.println("Table not found: " + e.getMessage());
            break;
        default:
            System.err.println("Database error: " + e.getMessage());
    }
}

Install with Tessl CLI

npx tessl i tessl/maven-com-h2database--h2

docs

tessl/maven-com-h2database--h2

jdbc.md.css-3qkkll{font-size:var(--chakra-font-sizes-sm);font-weight:var(--chakra-font-weights-normal);color:var(--chakra-colors-gray-300);}docs/

JDBC Connectivity

Core JDBC Classes

Driver

JdbcDataSource

JdbcConnectionPool

JdbcXAConnection

Connection URL Formats

Embedded Database URLs

Server Database URLs

Connection Parameters

Connection Properties

Connection Pooling Best Practices

Authentication and Security

Error Handling

jdbc.mddocs/