When I run "gradle eclipse -s", the following error message and exceptions are thrown. If I remove the jbpm4 from dependencies, then no error is thrown.

build.gradle
===========================================================================================
apply plugin: "war"
apply plugin: "eclipse"

sourceCompatibility = 1.5
targetCompatibility = 1.5

repositories {
// local repository is used to serve juel libraries
flatDir name: "localRepository", dirs: "lib"
localRepository

mavenCentral()
mavenRepo urls: ["https://repository.jboss.org/nexus/content/repositories/releases/"]
}

dependencies {
compile group: "com.google.gwt", name: "gwt-servlet", version: "2.0.4"
compile group: "org.jbpm.jbpm4", name: "jbpm-jpdl", version: "4.4"
providedCompile group: "com.google.gwt", name: "gwt-user", version: "2.0.4"
}

error message
=============================================================================================
D:\test>gradle eclipse -s
:eclipseClasspath
:eclipseProject
:eclipseWtp

FAILURE: Build failed with an exception.

• Where:
  Build file 'D:\test\build.gradle'

• What went wrong:
  Execution failed for task ':eclipseWtp'.
  Cause: Cannot get property 'value' on null object

• Try:
  Run with -S option to get the full (very verbose) stacktrace.

• Exception is:
  org.gradle.api.tasks.LocationAwareTaskExecutionException: Build file 'D:\test\bu
  ild.gradle'
  Execution failed for task ':eclipseWtp'.
  at org.gradle.api.internal.tasks.DefaultTaskExecuter.executeActions(Defa
  ultTaskExecuter.java:63)
  at org.gradle.api.internal.tasks.DefaultTaskExecuter.execute(DefaultTask
  Executer.java:41)
  at org.gradle.api.internal.project.taskfactory.PostExecutionAnalysisTask
  Executer.execute(PostExecutionAnalysisTaskExecuter.java:32)
  at org.gradle.api.internal.project.taskfactory.ExecutionShortCircuitTask
  Executer.execute(ExecutionShortCircuitTaskExecuter.java:50)
  at org.gradle.api.internal.tasks.SkipTaskExecuter.doExecute(SkipTaskExec
  uter.java:57)
  at org.gradle.api.internal.tasks.SkipTaskExecuter.execute(SkipTaskExecut
  er.java:35)
  at org.gradle.api.internal.tasks.ExecuteAtMostOnceTaskExecuter.execute(E
  xecuteAtMostOnceTaskExecuter.java:32)
  at org.gradle.api.internal.AbstractTask.execute(AbstractTask.java:231)
  at org.gradle.execution.DefaultTaskGraphExecuter.executeTask(DefaultTask
  GraphExecuter.java:167)
  at org.gradle.execution.DefaultTaskGraphExecuter.doExecute(DefaultTaskGr
  aphExecuter.java:160)
  at org.gradle.execution.DefaultTaskGraphExecuter.execute(DefaultTaskGrap
  hExecuter.java:78)
  at org.gradle.execution.TaskNameResolvingBuildExecuter.execute(TaskNameR
  esolvingBuildExecuter.java:161)
  at org.gradle.execution.DelegatingBuildExecuter.execute(DelegatingBuildE
  xecuter.java:54)
  at org.gradle.initialization.DefaultGradleLauncher.doBuildStages(Default
  GradleLauncher.java:153)
  at org.gradle.initialization.DefaultGradleLauncher.doBuild(DefaultGradle
  Launcher.java:107)
  at org.gradle.initialization.DefaultGradleLauncher.run(DefaultGradleLaun
  cher.java:75)
  at org.gradle.launcher.Main.execute(Main.java:93)
  at org.gradle.launcher.Main.main(Main.java:42)
  at org.gradle.launcher.GradleMain.main(GradleMain.java:49)
  Caused by: java.lang.NullPointerException: Cannot get property 'value' on null o
  bject
  at org.gradle.plugins.eclipse.model.internal.WtpFactory.createWbDependen
  tModuleEntry(WtpFactory.groovy:99)
  at org.gradle.plugins.eclipse.model.internal.WtpFactory$_getLibraries_cl
  osure7.doCall(WtpFactory.groovy:82)
  at org.gradle.plugins.eclipse.model.internal.WtpFactory.getLibraries(Wtp
  Factory.groovy:81)
  at org.gradle.plugins.eclipse.model.internal.WtpFactory.getEntriesFromCo
  nfigurations(WtpFactory.groovy:62)
  at org.gradle.plugins.eclipse.model.internal.WtpFactory$getEntriesFromCo
  nfigurations.callCurrent(Unknown Source)
  at org.gradle.plugins.eclipse.model.internal.WtpFactory.createWtp(WtpFac
  tory.groovy:42)
  at org.gradle.plugins.eclipse.model.internal.WtpFactory$createWtp.call(U
  nknown Source)
  at org.gradle.plugins.eclipse.model.internal.ModelFactory.createWtp(Mode
  lFactory.groovy:43)
  at org.gradle.plugins.eclipse.model.internal.ModelFactory$createWtp.call
  (Unknown Source)
  at org.gradle.plugins.eclipse.EclipseWtp.generateXml(EclipseWtp.groovy:1
  09)
  at org.gradle.api.internal.BeanDynamicObject.invokeMethod(BeanDynamicObj
  ect.java:158)
  at org.gradle.api.internal.CompositeDynamicObject.invokeMethod(Composite
  DynamicObject.java:93)
  at org.gradle.plugins.eclipse.EclipseWtp_Decorated.invokeMethod(Unknown
  Source)
  at org.gradle.util.ReflectionUtil.invoke(ReflectionUtil.groovy:23)
  at org.gradle.api.internal.project.taskfactory.AnnotationProcessingTaskF
  actory$2.execute(AnnotationProcessingTaskFactory.java:131)
  at org.gradle.api.internal.project.taskfactory.AnnotationProcessingTaskF
  actory$2.execute(AnnotationProcessingTaskFactory.java:129)
  at org.gradle.api.internal.tasks.DefaultTaskExecuter.executeActions(Defa
  ultTaskExecuter.java:55)
  ... 18 common frames omitted

BUILD FAILED