NullPointerException while building android app using ant

While building the android app using ant am getting the following exception. Couldn't figure out why these exception are thrown!!!

Execute:Java13CommandLauncher: Executing 'D:\Android-2.0\android-sdk-windows\platforms\android-1.5\tools\aapt.exe' with arguments:
'package'
'-f'
'-M'
'E:\manish_test\timetrack\client\static\android\AndroidManifest.xml'
'-S'
'E:\manish_test\timetrack\client\static\android\res'
'-A'
'E:\manish_test\timetrack\client\static\android\assets'
'-I'
'D:\Android-2.0\android-sdk-windows\platforms\android-1.5\android.jar'
'-F'
'C:\CLIENT_BUILDS\QA\3.0.9\Android\11-Feb-2010_b1\XoraTimeTrack.ap_'

The ' characters around the executable and arguments are not part of the command.

     [null]     (skipping index file 'E:\manish_test\timetrack\client\static\android\res\drawable\Thumbs.db')
Class org.apache.tools.ant.Project loaded from parent loader (parentFirst)
Finding class com.android.sdklib.internal.project.ProjectProperties$PropertyType
Loaded from D:\Android-2.0\android-sdk-windows\tools\lib\sdklib.jar com/android/sdklib/internal/project/ProjectProperties$PropertyType.class
Class java.lang.Enum loaded from parent loader (parentFirst)
Class com.android.sdklib.internal.project.ProjectProperties$PropertyType loaded from ant loader (parentFirst)
Finding class com.android.sdklib.internal.project.ProjectProperties
Loaded from D:\Android-2.0\android-sdk-windows\tools\lib\sdklib.jar com/android/sdklib/internal/project/ProjectProperties.class
Class com.android.sdklib.internal.project.ProjectProperties loaded from ant loader (parentFirst)
Class java.util.Map loaded from parent loader (parentFirst)
Class java.io.OutputStream loaded from parent loader (parentFirst)
Class java.io.FileOutputStream loaded from parent loader (parentFirst)
Class java.lang.Throwable loaded from parent loader (parentFirst)
Class java.lang.AssertionError loaded from parent loader (parentFirst)
Class java.lang.Class loaded from parent loader (parentFirst)
Class java.util.HashMap loaded from parent loader (parentFirst)
Finding class com.android.sdklib.internal.project.ApkConfigurationHelper
Loaded from D:\Android-2.0\android-sdk-windows\tools\lib\sdklib.jar com/android/sdklib/internal/project/ApkConfigurationHelper.class
Class com.android.sdklib.internal.project.ApkConfigurationHelper loaded from ant loader (parentFirst)
Finding class com.android.sdklib.internal.project.ApkSettings
Loaded from D:\Android-2.0\android-sdk-windows\tools\lib\sdklib.jar com/android/sdklib/internal/project/ApkSettings.class
Class com.android.sdklib.internal.project.ApkSettings loaded from ant loader (parentFirst)
  [antcall] Exiting E:\manish_test\timetrack\build\build-Android-1.0.xml.

BUILD FAILED
E:\manish_test\timetrack\build\build-Android-1.0.xml:371: The following error occurred while executing this line:
E:\manish_test\timetrack\build\build-Android-1.0.xml:302: java.lang.NullPointerException
    at org.apache.tools.ant.ProjectHelper.addLocationToBuildException(ProjectHelper.java:508)
    at org.apache.tools.ant.taskdefs.Ant.execute(Ant.java:418)
    at org.apache.tools.ant.taskdefs.CallTarget.execute(CallTarget.java:105)
    at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:288)
    at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)
    at org.apache.tools.ant.Task.perform(Task.java:348)
    at org.apache.tools.ant.Target.execute(Target.java:357)
    at org.apache.tools.ant.Target.performTasks(Target.java:385)
    at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1337)
    at org.apache.tools.ant.Project.executeTarget(Project.java:1306)
    at org.apache.tools.ant.helper.DefaultExecutor.executeTargets(DefaultExecutor.java:41)
    at org.apache.tools.ant.Project.executeTargets(Project.java:1189)
    at org.apache.tools.ant.开发者_JS百科Main.runBuild(Main.java:758)
    at org.apache.tools.ant.Main.startAnt(Main.java:217)
    at org.apache.tools.ant.launch.Launcher.run(Launcher.java:257)
    at org.apache.tools.ant.launch.Launcher.main(Launcher.java:104)
Caused by: E:\manish_test\timetrack\build\build-Android-1.0.xml:302: java.lang.NullPointerException
    at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:116)
    at org.apache.tools.ant.Task.perform(Task.java:348)
    at org.apache.tools.ant.Target.execute(Target.java:357)
    at org.apache.tools.ant.Target.performTasks(Target.java:385)
    at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1337)
    at org.apache.tools.ant.helper.SingleCheckExecutor.executeTargets(SingleCheckExecutor.java:38)
    at org.apache.tools.ant.Project.executeTargets(Project.java:1189)
    at org.apache.tools.ant.taskdefs.Ant.execute(Ant.java:416)
    ... 17 more
Caused by: java.lang.NullPointerException
    at com.android.sdklib.internal.project.ApkConfigurationHelper.getSettings(ApkConfigurationHelper.java:31)
    at com.android.ant.AaptExecLoopTask.execute(AaptExecLoopTask.java:137)
    at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:288)
    at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)
    ... 24 more
--- Nested Exception ---
E:\manish_test\timetrack\build\build-Android-1.0.xml:302: java.lang.NullPointerException
    at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:116)
    at org.apache.tools.ant.Task.perform(Task.java:348)
    at org.apache.tools.ant.Target.execute(Target.java:357)
    at org.apache.tools.ant.Target.performTasks(Target.java:385)
    at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1337)
    at org.apache.tools.ant.helper.SingleCheckExecutor.executeTargets(SingleCheckExecutor.java:38)
    at org.apache.tools.ant.Project.executeTargets(Project.java:1189)
    at org.apache.tools.ant.taskdefs.Ant.execute(Ant.java:416)
    at org.apache.tools.ant.taskdefs.CallTarget.execute(CallTarget.java:105)
    at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:288)
    at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)
    at org.apache.tools.ant.Task.perform(Task.java:348)
    at org.apache.tools.ant.Target.execute(Target.java:357)
    at org.apache.tools.ant.Target.performTasks(Target.java:385)
    at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1337)
    at org.apache.tools.ant.Project.executeTarget(Project.java:1306)
    at org.apache.tools.ant.helper.DefaultExecutor.executeTargets(DefaultExecutor.java:41)
    at org.apache.tools.ant.Project.executeTargets(Project.java:1189)
    at org.apache.tools.ant.Main.runBuild(Main.java:758)
    at org.apache.tools.ant.Main.startAnt(Main.java:217)
    at org.apache.tools.ant.launch.Launcher.run(Launcher.java:257)
    at org.apache.tools.ant.launch.Launcher.main(Launcher.java:104)
Caused by: java.lang.NullPointerException
    at com.android.sdklib.internal.project.ApkConfigurationHelper.getSettings(ApkConfigurationHelper.java:31)
    at com.android.ant.AaptExecLoopTask.execute(AaptExecLoopTask.java:137)
    at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:288)
    at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)
    ... 24 more
--- Nested Exception ---
java.lang.NullPointerException
    at com.android.sdklib.internal.project.ApkConfigurationHelper.getSettings(ApkConfigurationHelper.java:31)
    at com.android.ant.AaptExecLoopTask.execute(AaptExecLoopTask.java:137)
    at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:288)
    at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)
    at org.apache.tools.ant.Task.perform(Task.java:348)
    at org.apache.tools.ant.Target.execute(Target.java:357)
    at org.apache.tools.ant.Target.performTasks(Target.java:385)
    at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1337)
    at org.apache.tools.ant.helper.SingleCheckExecutor.executeTargets(SingleCheckExecutor.java:38)
    at org.apache.tools.ant.Project.executeTargets(Project.java:1189)
    at org.apache.tools.ant.taskdefs.Ant.execute(Ant.java:416)
    at org.apache.tools.ant.taskdefs.CallTarget.execute(CallTarget.java:105)
    at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:288)
    at sun.reflect.GeneratedMethodAccessor1.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:106)
    at org.apache.tools.ant.Task.perform(Task.java:348)
    at org.apache.tools.ant.Target.execute(Target.java:357)
    at org.apache.tools.ant.Target.performTasks(Target.java:385)
    at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1337)
    at org.apache.tools.ant.Project.executeTarget(Project.java:1306)
    at org.apache.tools.ant.helper.DefaultExecutor.executeTargets(DefaultExecutor.java:41)
    at org.apache.tools.ant.Project.executeTargets(Project.java:1189)
    at org.apache.tools.ant.Main.runBuild(Main.java:758)
    at org.apache.tools.ant.Main.startAnt(Main.java:217)
    at org.apache.tools.ant.launch.Launcher.run(Launcher.java:257)
    at org.apache.tools.ant.launch.Launcher.main(Launcher.java:104)

The last:

Caused by: java.lang.NullPointerException
    at com.android.sdklib.internal.project.ApkConfigurationHelper.getSettings(ApkConfigurationHelper.java:31)

is the important one here.
You need to check the ApkConfigurationHelper source code and see why it could throw an NPE here.

Found the solution exception was thrown due to the hardcoding for property file name and location. ApkConfigurationHelper expects the default.properties file in the ant projects base directory and the property split.density should be set in this file. Its working like a charm now.

Thanks all for your all help..

-- Manish