After running for awhile, Hudson gives the following exception.
This is found in 1.123 version
Restarting Tomcat will fix the issue.

FATAL: command execution failed
java.io.IOException: Too many open files
at java.lang.UNIXProcess.forkAndExec(Native Method)
at java.lang.UNIXProcess.<init>(UNIXProcess.java:53)
at java.lang.ProcessImpl.start(ProcessImpl.java:65)
at java.lang.ProcessBuilder.start(ProcessBuilder.java:451)
at java.lang.Runtime.exec(Runtime.java:591)
at hudson.Proc$LocalProc.<init>(Proc.java:79)
at hudson.Launcher$LocalLauncher.launch(Launcher.java:168)
at hudson.Launcher.launch(Launcher.java:83)
at hudson.Launcher.launch(Launcher.java:71)
at hudson.tasks.Ant.perform(Ant.java:114)
at hudson.model.Build$RunnerImpl.build(Build.java:147)
at hudson.model.Build$RunnerImpl.doRun(Build.java:127)
at hudson.model.AbstractBuild$AbstractRunner.run(AbstractBuild.java:129)
at hudson.model.Run.run(Run.java:562)
at hudson.model.Build.run(Build.java:107)
at hudson.model.ResourceController.execute(ResourceController.java:66)
at hudson.model.Executor.run(Executor.java:59)
finished: FAILURE