Erro "unsupported Java version" no android

Galera, estou utilizando o jack para suporte de java 8 no app pra lib Samuel…, mas quando eu compilo a dependencia do javax, acontece o seguinte erro:

Error:Jar transformation: class files coming from an unsupported Java version
Error:Execution failed for task ':app:transformClassesWithPreJackPackagedLibrariesForDebug'.
> com.android.build.api.transform.TransformException: com.android.builder.core.JackToolchain$ToolchainException: Jack compilation exception

Esse é meu Build:

android {
    compileSdkVersion 25
    buildToolsVersion "26.0.0"
    defaultConfig {
        applicationId "br.com.visdom.pdv"
        minSdkVersion 15
        targetSdkVersion 25
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
        vectorDrawables.useSupportLibrary = true
        jackOptions { enabled true }
        multiDexEnabled true
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
    compileOptions {
        incremental false
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
}
allprojects {
    repositories {
        mavenCentral()
        maven { url "https://jitpack.io" }
        maven { url "http://www.autocomsistemas.com.br:8081/nexus/content/repositories/autocom/" }
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
        exclude group: 'com.android.support', module: 'support-annotations'
    })
    compile 'com.android.support.constraint:constraint-layout:1.0.2'
    compile 'com.android.support:appcompat-v7:25.3.1'
    compile 'com.android.support:recyclerview-v7:25.3.1'
    compile 'com.android.support:design:25.3.1'
    compile 'com.android.support:support-vector-drawable:25.3.1'
    compile 'com.android.support:support-v4:25.3.1'
    //libs externas
    compile files('libs/ePOS2.jar')
    compile 'com.github.clans:fab:1.6.4'
    compile 'com.github.PhilJay:MPAndroidChart:v3.0.2'
    compile 'br.com.samuelweb:java-nfe:3.10.7'
    compile 'javax.xml.bind:jaxb-api:2.3.0'
    testCompile 'junit:junit:4.12'
}