/**
 * Returns a database connection for the specified datasource
 * @param db - ex. "jdbc/DatasourceXyz"
 * @return db Connection
 * @throws Exception
 */
public static Connection getDbConnection(String db) throws Exception {
    java.sql.Connection conn = null;

    try {
        LOG.debug("getting db connection for " + db + " ...");

        javax.naming.Context initCtx = new javax.naming.InitialContext();
        javax.naming.Context envCtx = (javax.naming.Context) initCtx.lookup("java:comp/env");
        javax.sql.DataSource ds = (javax.sql.DataSource) envCtx.lookup(db);
        conn = ds.getConnection();

        initCtx.close();
        LOG.debug("got db connection for " + db);
        LOG.debug("url = " + conn.getMetaData().getURL());

    } catch (Exception e) {
        String message = String.format("Exception thrown while creating a JDBC connection for %s: %s", db,
                e.getMessage());
        throw new Exception(message);
    }

    return conn;
}

<Context>
<WatchedResource>WEB-INF/web.xml</WatchedResource>
<WatchedResource>${catalina.base}/conf/web.xml</WatchedResource>
<!-- environment-specific jdbc data sources: -->
<Resource name="jdbc/DatasourceXyz" auth="Container" type="javax.sql.DataSource" driverClassName="oracle.jdbc.OracleDriver" url="jdbc:oracle:thin:@hostname:1521:database" username="someUser" password="***" maxTotal="20" maxIdle="10" maxWaitMillis="60000"/>
<!-- set other jdbc data sources below: -->

public static Connection getDbConnection(String db) throws Exception {
    java.sql.Connection conn = null;

    try {
        LOG.debug("getting db connection for " + db + " ...");

        // Get the SampleUtilService from the Bridge
        SampleUtilService sampleUtilService = SpringContextBridge.services().getSampleUtilService();

        // Get DataSource from the JndiObjectFactoryBean
        javax.sql.DataSource ds = sampleUtilService.getDataSourcefromFactoryBean(db);

        conn = ds.getConnection();

        LOG.debug("got db connection for " + db);
        LOG.debug("url = " + conn.getMetaData().getURL());

    } catch (Exception e) {
        String message = String.format("Exception thrown while creating a JDBC connection for %s: %s", db,
                e.getMessage());
        throw new Exception(message);
    }

    return conn;
}

@Bean(destroyMethod="")
public DataSource jndiDataSource() throws IllegalArgumentException, NamingException {
    JndiObjectFactoryBean bean = new JndiObjectFactoryBean();
    bean.setJndiName("java:comp/env/jdbc/myDataSource");
    bean.setProxyInterface(DataSource.class);
    bean.setLookupOnStartup(false);
    bean.afterPropertiesSet();
    return (DataSource)bean.getObject();
}

DataSource dataSource =
            (DataSource) new InitialContext().lookup("java:comp/env/jdbc/myDataSource");