After a while, svn updates stop working on Hudson. The job's console output shows:

started
Updating svn+ssh://...
ERROR: Failed to update svn+ssh://...
org.tmatesoft.svn.core.SVNException: svn: Cannot connect to 'svn+ssh://...':
Sorry, this connection is closed.
at
org.tmatesoft.svn.core.internal.wc.SVNErrorManager.error(SVNErrorManager.java:63)
at
org.tmatesoft.svn.core.internal.io.svn.SVNGanymedConnector.open(SVNGanymedConnector.java:129)
at org.tmatesoft.svn.core.internal.io.svn.SVNConnection.open(SVNConnection.java:60)
at
org.tmatesoft.svn.core.internal.io.svn.SVNRepositoryImpl.openConnection(SVNRepositoryImpl.java:970)
at
org.tmatesoft.svn.core.internal.io.svn.SVNRepositoryImpl.getDatedRevision(SVNRepositoryImpl.java:159)
at
org.tmatesoft.svn.core.wc.SVNBasicClient.getRevisionNumber(SVNBasicClient.java:346)
at org.tmatesoft.svn.core.wc.SVNUpdateClient.doUpdate(SVNUpdateClient.java:159)
at hudson.scm.SubversionSCM$CheckOutTask.invoke(SubversionSCM.java:368)
at hudson.scm.SubversionSCM$CheckOutTask.invoke(SubversionSCM.java:341)
at hudson.FilePath.act(FilePath.java:280)
at hudson.scm.SubversionSCM.checkout(SubversionSCM.java:338)
at hudson.scm.SubversionSCM.checkout(SubversionSCM.java:295)
at hudson.model.AbstractProject.checkout(AbstractProject.java:485)
at hudson.model.AbstractBuild$AbstractRunner.checkout(AbstractBuild.java:160)
at hudson.model.AbstractBuild$AbstractRunner.run(AbstractBuild.java:126)
at hudson.model.Run.run(Run.java:573)
at hudson.model.Build.run(Build.java:107)
at hudson.model.ResourceController.execute(ResourceController.java:66)
at hudson.model.Executor.run(Executor.java:59)
Caused by: java.io.IOException: Sorry, this connection is closed.
at ch.ethz.ssh2.transport.TransportManager.sendMessage(TransportManager.java:635)
at ch.ethz.ssh2.channel.ChannelManager.openSessionChannel(ChannelManager.java:566)
at ch.ethz.ssh2.Session.<init>(Session.java:39)
at ch.ethz.ssh2.Connection.openSession(Connection.java:965)
at
org.tmatesoft.svn.core.internal.io.svn.SVNGanymedSession$SSHConnectionInfo.openSession(SVNGanymedSession.java:421)
at
org.tmatesoft.svn.core.internal.io.svn.SVNGanymedConnector.open(SVNGanymedConnector.java:89)
... 17 more
Caused by: java.net.SocketException: Connection reset
at java.net.SocketInputStream.read(SocketInputStream.java:168)
at
ch.ethz.ssh2.crypto.cipher.CipherInputStream.fill_buffer(CipherInputStream.java:41)
at
ch.ethz.ssh2.crypto.cipher.CipherInputStream.internal_read(CipherInputStream.java:52)
at ch.ethz.ssh2.crypto.cipher.CipherInputStream.getBlock(CipherInputStream.java:79)
at ch.ethz.ssh2.crypto.cipher.CipherInputStream.read(CipherInputStream.java:108)
at
ch.ethz.ssh2.transport.TransportConnection.receiveMessage(TransportConnection.java:231)
at ch.ethz.ssh2.transport.TransportManager.receiveLoop(TransportManager.java:669)
at ch.ethz.ssh2.transport.TransportManager$1.run(TransportManager.java:468)
at java.lang.Thread.run(Thread.java:595)
Publishing Javadoc
Sending e-mails to: ...
finished: FAILURE

Restarting tomcat and running the build again fixes it for a while.