error building android core [closed]

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I'm following the instructions on http://docs.rosjava.googlecode.com/hg/android_core/html/building.html , but when i build android_core , i came across this kind of problem. I have made the rosjava_core, and the only code i've changed is when installing ant i use "sudo apt-get install ant ant-optional" instead of "sudo apt-get install ant1.8 ant1.8-optional". I have already installed SDK(not from code) and plug-in for eclipse but i have never configured that. can anybody help me on that? Thanks a lot.

Building > :android_acm_serial:deployLibs > Resolving dependencies ':android_a:android_acm_serial:deployLibs UP-TO-DATE :android_acm_serial:updateProject

FAILURE: Build failed with an exception.

• What went wrong: Execution failed for task ':android_acm_serial:updateProject'.

  A problem occurred starting command 'android'.

• Try: Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.

BUILD FAILED

and that's what i get when run --stacktrace

:android_acm_serial:deployLibs UP-TO-DATE :android_acm_serial:updateProject

FAILURE: Build failed with an exception.

• What went wrong: Execution failed for task ':android_acm_serial:updateProject'.

  A problem occurred starting command 'android'.

• Try: Run with --info or --debug option to get more log output.

• Exception is: org.gradle.api.tasks.TaskExecutionException: Execution failed for task ':android_acm_serial:updateProject'. at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.executeActions(ExecuteActionsTaskExecuter.java:68) at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.execute(ExecuteActionsTaskExecuter.java:46) at org.gradle.api.internal.tasks.execution.PostExecutionAnalysisTaskExecuter.execute(PostExecutionAnalysisTaskExecuter.java:34) at org.gradle.api.internal.changedetection.CacheLockHandlingTaskExecuter$1.run(CacheLockHandlingTaskExecuter.java:34) at org.gradle.cache.internal.DefaultCacheAccess$2.create(DefaultCacheAccess.java:200) at org.gradle.cache.internal.DefaultCacheAccess.longRunningOperation(DefaultCacheAccess.java:172) at org.gradle.cache.internal.DefaultCacheAccess.longRunningOperation(DefaultCacheAccess.java:198) at org.gradle.cache.internal.DefaultPersistentDirectoryStore.longRunningOperation(DefaultPersistentDirectoryStore.java:111) at org.gradle.api.internal.changedetection.DefaultTaskArtifactStateCacheAccess.longRunningOperation(DefaultTaskArtifactStateCacheAccess.java:83) at org.gradle.api.internal.changedetection.CacheLockHandlingTaskExecuter.execute(CacheLockHandlingTaskExecuter.java:32) at org.gradle.api.internal.tasks.execution.SkipUpToDateTaskExecuter.execute(SkipUpToDateTaskExecuter.java:55) at org.gradle.api.internal.tasks.execution.ValidatingTaskExecuter.execute(ValidatingTaskExecuter.java:57) at org.gradle.api.internal.tasks.execution.SkipEmptySourceFilesTaskExecuter.execute(SkipEmptySourceFilesTaskExecuter.java:41) at org.gradle.api.internal.tasks.execution.SkipTaskWithNoActionsExecuter.execute(SkipTaskWithNoActionsExecuter.java:51) at org.gradle.api.internal.tasks.execution.SkipOnlyIfTaskExecuter.execute(SkipOnlyIfTaskExecuter.java:52) at org.gradle.api.internal.tasks.execution.ExecuteAtMostOnceTaskExecuter.execute(ExecuteAtMostOnceTaskExecuter.java:42) at org.gradle.api.internal.AbstractTask.executeWithoutThrowingTaskFailure(AbstractTask.java:247) at org.gradle.execution.DefaultTaskGraphExecuter.executeTask(DefaultTaskGraphExecuter.java:192) at org.gradle.execution.DefaultTaskGraphExecuter.doExecute(DefaultTaskGraphExecuter.java:177) at org.gradle.execution.DefaultTaskGraphExecuter.execute(DefaultTaskGraphExecuter.java:83) at org.gradle.execution.SelectedTaskExecutionAction.execute(SelectedTaskExecutionAction.java:36) at org.gradle.execution.DefaultBuildExecuter.execute(DefaultBuildExecuter.java:61) at org.gradle.execution.DefaultBuildExecuter.access$200(DefaultBuildExecuter.java:23) at org.gradle.execution.DefaultBuildExecuter$2.proceed(DefaultBuildExecuter.java:67) at org.gradle.api.internal.changedetection.TaskCacheLockHandlingBuildExecuter$1.run(TaskCacheLockHandlingBuildExecuter.java:31) at org.gradle.cache.internal.DefaultCacheAccess$1.create(DefaultCacheAccess.java:111) at org.gradle.cache.internal.DefaultCacheAccess.useCache(DefaultCacheAccess.java:126) at org.gradle.cache.internal.DefaultCacheAccess.useCache ...