title: Apache Derby startup error java.lang.SecurityException: sealing violation: package org.apache.derby.impl.services.timer is sealed
body: <p>I am using Ubuntu 14.04 and have installed Derby 10.12.1.1. I have followed installation instructions from Apache website.</p>
  
  <p>My <code>CLASSPATH</code> has been set as</p>
  
  <pre><code>/usr/local/hadoop/lib/*:/usr/local/hive/lib/*:/usr/local/derby/lib/derbynet.jar:/usr/local/derby/lib/derbytools.jar
  </code></pre>
  
  <p>When I try to start Derby  </p>
  
  <pre><code>hduser@HadoopMaster:/usr/local/derby/data$ /usr/local/derby/bin/startNetworkServer
  </code></pre>
  
  <p>I get </p>
  
  <pre><code>Tue Nov 10 23:50:18 AEDT 2015 : Security manager installed using the Basic server security policy.
  java.lang.SecurityException: sealing violation: package org.apache.derby.impl.services.timer is sealed
      at java.net.URLClassLoader.getAndVerifyPackage(URLClassLoader.java:399)
      at java.net.URLClassLoader.definePackageInternal(URLClassLoader.java:419)
      at java.net.URLClassLoader.defineClass(URLClassLoader.java:451)
      at java.net.URLClassLoader.access$100(URLClassLoader.java:73)
      at java.net.URLClassLoader$1.run(URLClassLoader.java:368)
      at java.net.URLClassLoader$1.run(URLClassLoader.java:362)
      at java.security.AccessController.doPrivileged(Native Method)
      at java.net.URLClassLoader.findClass(URLClassLoader.java:361)
      at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
      at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
      at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
      at java.lang.ClassLoader.defineClass1(Native Method)
      at java.lang.ClassLoader.defineClass(ClassLoader.java:760)
      at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
      at java.net.URLClassLoader.defineClass(URLClassLoader.java:467)
      at java.net.URLClassLoader.access$100(URLClassLoader.java:73)
      at java.net.URLClassLoader$1.run(URLClassLoader.java:368)
      at java.net.URLClassLoader$1.run(URLClassLoader.java:362)
      at java.security.AccessController.doPrivileged(Native Method)
      at java.net.URLClassLoader.findClass(URLClassLoader.java:361)
      at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
      at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
      at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
      at java.lang.Class.forName0(Native Method)
      at java.lang.Class.forName(Class.java:264)
      at org.apache.derby.impl.services.monitor.BaseMonitor.getImplementations(Unknown Source)
      at org.apache.derby.impl.services.monitor.BaseMonitor.getDefaultImplementations(Unknown Source)
      at org.apache.derby.impl.services.monitor.BaseMonitor.runWithState(Unknown Source)
      at org.apache.derby.impl.services.monitor.FileMonitor.&lt;init&gt;(Unknown Source)
      at org.apache.derby.iapi.services.monitor.Monitor.startMonitor(Unknown Source)
      at org.apache.derby.iapi.jdbc.JDBCBoot$1.run(Unknown Source)
      at java.security.AccessController.doPrivileged(Native Method)
      at org.apache.derby.iapi.jdbc.JDBCBoot.boot(Unknown Source)
      at org.apache.derby.iapi.jdbc.JDBCBoot.boot(Unknown Source)
      at org.apache.derby.jdbc.EmbeddedDriver.boot(Unknown Source)
      at org.apache.derby.jdbc.EmbeddedDriver.&lt;clinit&gt;(Unknown Source)
      at java.lang.Class.forName0(Native Method)
      at java.lang.Class.forName(Class.java:264)
      at org.apache.derby.impl.drda.NetworkServerControlImpl.startNetworkServer(Unknown Source)
      at org.apache.derby.impl.drda.NetworkServerControlImpl.blockingStart(Unknown Source)
      at org.apache.derby.impl.drda.NetworkServerControlImpl.executeWork(Unknown Source)
      at org.apache.derby.drda.NetworkServerControl.main(Unknown Source)
  Exception in thread "main" java.lang.ExceptionInInitializerError
      at java.lang.Class.forName0(Native Method)
      at java.lang.Class.forName(Class.java:264)
      at org.apache.derby.impl.drda.NetworkServerControlImpl.startNetworkServer(Unknown Source)
      at org.apache.derby.impl.drda.NetworkServerControlImpl.blockingStart(Unknown Source)
      at org.apache.derby.impl.drda.NetworkServerControlImpl.executeWork(Unknown Source)
      at org.apache.derby.drda.NetworkServerControl.main(Unknown Source)
  Caused by: java.lang.SecurityException: sealing violation: package org.apache.derby.impl.services.timer is sealed
      at java.net.URLClassLoader.getAndVerifyPackage(URLClassLoader.java:399)
      at java.net.URLClassLoader.definePackageInternal(URLClassLoader.java:419)
      at java.net.URLClassLoader.defineClass(URLClassLoader.java:451)
      at java.net.URLClassLoader.access$100(URLClassLoader.java:73)
      at java.net.URLClassLoader$1.run(URLClassLoader.java:368)
      at java.net.URLClassLoader$1.run(URLClassLoader.java:362)
      at java.security.AccessController.doPrivileged(Native Method)
      at java.net.URLClassLoader.findClass(URLClassLoader.java:361)
      at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
      at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
      at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
      at java.lang.ClassLoader.defineClass1(Native Method)
      at java.lang.ClassLoader.defineClass(ClassLoader.java:760)
      at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
      at java.net.URLClassLoader.defineClass(URLClassLoader.java:467)
      at java.net.URLClassLoader.access$100(URLClassLoader.java:73)
      at java.net.URLClassLoader$1.run(URLClassLoader.java:368)
      at java.net.URLClassLoader$1.run(URLClassLoader.java:362)
      at java.security.AccessController.doPrivileged(Native Method)
      at java.net.URLClassLoader.findClass(URLClassLoader.java:361)
      at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
      at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
      at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
      at java.lang.Class.forName0(Native Method)
      at java.lang.Class.forName(Class.java:264)
      at org.apache.derby.impl.services.monitor.BaseMonitor.getImplementations(Unknown Source)
      at org.apache.derby.impl.services.monitor.BaseMonitor.getDefaultImplementations(Unknown Source)
      at org.apache.derby.impl.services.monitor.BaseMonitor.runWithState(Unknown Source)
      at org.apache.derby.impl.services.monitor.FileMonitor.&lt;init&gt;(Unknown Source)
      at org.apache.derby.iapi.services.monitor.Monitor.startMonitor(Unknown Source)
      at org.apache.derby.iapi.jdbc.JDBCBoot$1.run(Unknown Source)
      at java.security.AccessController.doPrivileged(Native Method)
      at org.apache.derby.iapi.jdbc.JDBCBoot.boot(Unknown Source)
      at org.apache.derby.iapi.jdbc.JDBCBoot.boot(Unknown Source)
      at org.apache.derby.jdbc.EmbeddedDriver.boot(Unknown Source)
      at org.apache.derby.jdbc.EmbeddedDriver.&lt;clinit&gt;(Unknown Source)
      ... 6 more
  </code></pre>