If an Ant installation in a freestyle project is selected where the ANT_HOME is
not correctly set (e.g. to a directory that does not exist) the console output
just prints the appended Exception. The Exception is not very informative. It
should be something like: "The selected Ant installation for the freestyle
project is broken" or "Cannot find ANT_HOME/bin/ant, please check your
configuration (System- & Projectconfiguration)"

...
FATAL: 0
java.lang.ArrayIndexOutOfBoundsException: 0
at java.lang.ProcessBuilder.start(ProcessBuilder.java:443)
at hudson.Proc$LocalProc.<init>(Proc.java:104)
at hudson.Proc$LocalProc.<init>(Proc.java:82)
at hudson.Launcher$LocalLauncher.createLocalProc(Launcher.java:310)
at hudson.Launcher$LocalLauncher.launch(Launcher.java:301)
at hudson.Launcher.launch(Launcher.java:139)
at hudson.Launcher.launch(Launcher.java:91)
at hudson.tasks.Ant.perform(Ant.java:200)
at hudson.model.Build$RunnerImpl.build(Build.java:134)
at hudson.model.Build$RunnerImpl.doRun(Build.java:109)
at hudson.model.AbstractBuild$AbstractRunner.run(AbstractBuild.java:231)
at hudson.model.Run.run(Run.java:786)
at hudson.model.Build.run(Build.java:84)
at hudson.model.ResourceController.execute(ResourceController.java:70)
at hudson.model.Executor.run(Executor.java:88)