Derby can't create database while running within a webapp? - tomcat7

Question

I have this code in a web application (tomcat7):
public InitBean() throws UnknownHostException, Exception {
NetworkServerControl server = new NetworkServerControl(
InetAddress.getByName("localhost"), 1527);
server.start(new PrintWriter(System.err));
String driver = "org.apache.derby.jdbc.ClientDriver";
Class.forName(driver).newInstance();
Connection conn = DriverManager.getConnection("jdbc:derby://localhost:1527/ctc;create=true");
}
The intent is to create a Derby database that can accessed from both inside and outside of the webapp. This is an uncommon use-case involving database ETL tools.
I am getting this error:
Sep 14, 2015 7:23:19 AM org.apache.catalina.core.StandardContext loadOnStartup
SEVERE: Servlet /map threw load() exception
ERROR XJ041: DERBY SQL error: ERRORCODE: 40000, SQLSTATE: XJ041, SQLERRMC: Failed to create database 'ctc', see the next exception for details.::SQLSTATE: XBM02
at org.apache.derby.client.am.ClientConnection.completeSqlca(Unknown Source)
at org.apache.derby.client.net.NetConnectionReply.parseRdbAccessFailed(Unknown Source)
at org.apache.derby.client.net.NetConnectionReply.parseAccessRdbError(Unknown Source)
at org.apache.derby.client.net.NetConnectionReply.parseACCRDBreply(Unknown Source)
at org.apache.derby.client.net.NetConnectionReply.readAccessDatabase(Unknown Source)
at org.apache.derby.client.net.NetConnection.readSecurityCheckAndAccessRdb(Unknown Source)
at org.apache.derby.client.net.NetConnection.flowSecurityCheckAndAccessRdb(Unknown Source)
at org.apache.derby.client.net.NetConnection.flowUSRIDONLconnect(Unknown Source)
at org.apache.derby.client.net.NetConnection.flowConnect(Unknown Source)
at org.apache.derby.client.net.NetConnection.<init>(Unknown Source)
at org.apache.derby.client.net.ClientJDBCObjectFactoryImpl.newNetConnection(Unknown Source)
at org.apache.derby.jdbc.ClientDriver.connect(Unknown Source)
at java.sql.DriverManager.getConnection(DriverManager.java:664)
at java.sql.DriverManager.getConnection(DriverManager.java:270)
at com.ctc.service.InitBean.<init>(InitBean.java:40)
This is on Windows 7, 64-bit, Java 8, with Tomcat 7.
What could be the problem?
UPDATE
The exact same code works fine in stand-alone app (J2SE / JUnit), but it fails under Tomcat / Springframework.