gradle无法编译app：dexDebug

Question

当我编译时，我得到一个关于dexDebug的错误，我无法解决。我正在使用JSON简单库，jReddit库和Apache Commons库。我以前从未见过这个错误，也不知道如何修复它。提前谢谢！

    apply plugin: 'com.android.application'

android {
    compileSdkVersion 22
    buildToolsVersion "21.1.2"

    defaultConfig {
        applicationId "net.techredesign.uiforreddit"
        minSdkVersion 21
        targetSdkVersion 22
        versionCode 1
        versionName "1.0"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])

    compile group: 'com.github.jreddit', name: 'jreddit', version: '1.0.3'
    compile "com.googlecode.json-simple:json-simple:1.1"
    compile group: 'commons-io', name: 'commons-io', version: '2.0.1'



}

这是错误：

Error:Execution failed for task ':app:dexDebug'.
> com.android.ide.common.process.ProcessException: org.gradle.process.internal.ExecException: Process 'command '/Library/Java/JavaVirtualMachines/jdk1.8.0_31.jdk/Contents/Home/bin/java'' finished with non-zero exit value 2

非常感谢任何帮助!!