Resolving ant errors can be a pain sometimes because of the vague error messages you get on the console. Yesterday I was getting a "Process fork failed." error on my Junit task and all I got on the console was
BUILD FAILED
C:\work\builds\build.xml:58: Process fork failed.
I wasted a couple of hours on google looking for an answer and after failing to fix the issue with several suggested solutions, I stumbled upon one post that suggested enabling the verbose output of Ant. All you had to do was pass -verbose as a command line parameter to ant
ant -verbose <target>
That made ant display lot of details including the actual exception. In my case it was:
C:\work\build\build.xml:58: Process fork failed.
at org.apache.tools.ant.taskdefs.optional.junit.JUnitTask.executeAsForked(JUnitTask.java:871)
at org.apache.tools.ant.taskdefs.optional.junit.JUnitTask.execute(JUnitTask.java:679)
at org.apache.tools.ant.taskdefs.optional.junit.JUnitTask.executeOrQueue(JUnitTask.java:1413)
at org.apache.tools.ant.taskdefs.optional.junit.JUnitTask.execute(JUnitTask.java:633)
at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:275)
at org.apache.tools.ant.Task.perform(Task.java:364)
at org.apache.tools.ant.Target.execute(Target.java:341)
at org.apache.tools.ant.Target.performTasks(Target.java:369)
at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1216)
at org.apache.tools.ant.Project.executeTarget(Project.java:1185)
at org.apache.tools.ant.helper.DefaultExecutor.executeTargets(DefaultExecutor.java:40)
at org.apache.tools.ant.Project.executeTargets(Project.java:1068)
at org.apache.tools.ant.Main.runBuild(Main.java:668)
at org.apache.tools.ant.Main.startAnt(Main.java:187)
at org.apache.tools.ant.launch.Launcher.run(Launcher.java:246)
at org.apache.tools.ant.launch.Launcher.main(Launcher.java:67)
Caused by: java.io.IOException: CreateProcess: C:\bea92\jdk150_04\jre\bin\java.exe ...
I found the issue a little bit above the exception on the console and it was the massive classpath value passed into the java.exe. Obviously the Windows command line has a limitation on the length of command line arguments and the value for classpath was exceeding it.
When I checked the build file I found the error, where it was adding the files in a directory instead of the directory into the classpath. Fixed that small error and all was fine again.
Anyway glad I got to know about the verbose switch in Ant and hopefully I wouldn't have to waste a lot of time again fixing ant issues again.