Findbugs Gradle plugin failed

Question

I'm trying to use findbugs plugin in gradle, but it's not working. Here is the snippet gradle configuration.

apply plugin: 'findbugs'

dependencies {
    findbugsPlugins fileTree(dir: "$toolsHome/findbugs", include: '*.jar')
}

findbugs {
    toolVersion = "3.0.1"
    sourceSets = [sourceSets.main]
    ignoreFailures = true
    reportsDir = file("$project.buildDir/findbugsReports")
    effort = "max"
    reportLevel = "low"
    excludeBugsFilter = file(toolsHome + File.separator + "findbugs" + File.separator + "findbugs-exclude.xml")
}

Stacktrace: Gradle Stacktrace

Does anyone can pointing to me what's wrong with my configuration?