Execution failed for task ':app:minifyReleaseWithR8'.java.lang.NullPointerException (no error message)

Question

when id update android studio to 3.6 android gradle tools to 3.6.0 ,there is a problem.when I generate sign apk,I got an exception，it is like this

 Execution failed for task ':app:minifyReleaseWithR8'.java.lang.NullPointerException (no error message)
* Exception is:
10:35:36.483 [ERROR] [org.gradle.internal.buildevents.BuildExceptionReporter] org.gradle.api.tasks.TaskExecutionException: Execution failed for task ':app:minifyReleaseWithR8'.
10:35:36.483 [ERROR] [org.gradle.internal.buildevents.BuildExceptionReporter]   at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter$3.accept(ExecuteActionsTaskExecuter.java:166)
10:35:36.483 [ERROR] [org.gradle.internal.buildevents.BuildExceptionReporter]   at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter$3.accept(ExecuteActionsTaskExecuter.java:163)
10:35:36.483 [ERROR] [org.gradle.internal.buildevents.BuildExceptionReporter]   at org.gradle.internal.Try$Failure.ifSuccessfulOrElse(Try.java:191)
10:35:36.483 [ERROR] [org.gradle.internal.buildevents.BuildExceptionReporter]   at org.gradle.api.internal.tasks.execution.ExecuteActionsTaskExecuter.execute(ExecuteActionsTaskExecuter.java:156)
10:35:36.484 [ERROR] [org.gradle.internal.buildevents.BuildExceptionReporter]   at org.gradle.api.internal.tasks.execution.ValidatingTaskExecuter.execute(ValidatingTaskExecuter.java:62)
10:35:36.484 [ERROR] [org.gradle.internal.buildevents.BuildExceptionReporter]   at org.gradle.api.internal.tasks.execution.SkipEmptySourceFilesTaskExecuter.execute(SkipEmptySourceFilesTaskExecuter.java:108)
10:35:36.484 [ERROR] [org.gradle.internal.buildevents.BuildExceptionReporter]   at org.gradle.api.internal.tasks.execution.ResolveBeforeExecutionOutputsTaskExecuter.execute(ResolveBeforeExecutionOutputsTaskExecuter.java:67)
10:35:36.484 [ERROR] [org.gradle.internal.buildevents.BuildExceptionReporter]   at org.gradle.api.internal.tasks.execution.ResolveAfterPreviousExecutionStateTaskExecuter.execute(ResolveAfterPreviousExecutionStateTaskExecuter.java:46)
....
Caused by: java.lang.NullPointerException
10:35:36.486 [ERROR] [org.gradle.internal.buildevents.BuildExceptionReporter]   at com.android.tools.r8.naming.A.a(:7)
10:35:36.486 [ERROR] [org.gradle.internal.buildevents.BuildExceptionReporter]   at com.android.tools.r8.naming.A.c(:1)
10:35:36.487 [ERROR] [org.gradle.internal.buildevents.BuildExceptionReporter]   at com.android.tools.r8.naming.w.a(:71)
10:35:36.487 [ERROR] [org.gradle.internal.buildevents.BuildExceptionReporter]   at com.android.tools.r8.naming.w.a(:54)
10:35:36.487 [ERROR] [org.gradle.internal.buildevents.BuildExceptionReporter]   at com.android.tools.r8.naming.w.a(:61)
10:35:36.487 [ERROR] [org.gradle.internal.buildevents.BuildExceptionReporter]   at com.android.tools.r8.naming.w.a(:61)
10:35:36.487 [ERROR] [org.gradle.internal.buildevents.BuildExceptionReporter]   at com.android.tools.r8.naming.w.a(:29)
10:35:36.487 [ERROR] [org.gradle.internal.buildevents.BuildExceptionReporter]   at com.android.tools.r8.naming.G.a(:25)
10:35:36.487 [ERROR] [org.gradle.internal.buildevents.BuildExceptionReporter]   at com.android.tools.r8.R8.a(:615)
10:35:36.488 [ERROR] [org.gradle.internal.buildevents.BuildExceptionReporter]   at com.android.tools.r8.R8.c(:1)
10:35:36.488 [ERROR] [org.gradle.internal.buildevents.BuildExceptionReporter]   at com.android.tools.r8.R8.b(:1)
10:35:36.488 [ERROR] [org.gradle.internal.buildevents.BuildExceptionReporter]   at com.android.tools.r8.utils.O.a(:30)
10:35:36.488 [ERROR] [org.gradle.internal.buildevents.BuildExceptionReporter]   at com.android.tools.r8.R8.runForTesting(:3)
10:35:36.488 [ERROR] [org.gradle.internal.buildevents.BuildExceptionReporter]   at com.android.tools.r8.R8.run(:3)
10:35:36.488 [ERROR] [org.gradle.internal.buildevents.BuildExceptionReporter]   at com.android.builder.dexing.R8Tool.runR8(r8Tool.kt:215)
10:35:36.488 [ERROR] [org.gradle.internal.buildevents.BuildExceptionReporter]   at com.android.build.gradle.internal.tasks.R8Task$Companion.shrink(R8Task.kt:387)
10:35:36.488 [ERROR] [org.gradle.internal.buildevents.BuildExceptionReporter]   at com.android.build.gradle.internal.tasks.R8Task.doTaskAction(R8Task.kt:268)
10:35:36.488 [ERROR] [org.gradle.internal.buildevents.BuildExceptionReporter]   at com.android.build.gradle.internal.tasks.NonIncrementalTask$taskAction$$inlined$recordTaskAction$1.invoke(AndroidVariantTask.kt:73)
10:35:36.488 [ERROR] [org.gradle.internal.buildevents.BuildExceptionReporter]   at com.android.build.gradle.internal.tasks.NonIncrementalTask$taskAction$$inlined$recordTaskAction$1.invoke(AndroidVariantTask.kt:34)
10:35:36.488 [ERROR] [org.gradle.internal.buildevents.BuildExceptionReporter]   at com.android.build.gradle.internal.tasks.Blocks.recordSpan(Blocks.java:91)
10:35:36.488 [ERROR] [org.gradle.internal.buildevents.BuildExceptionReporter]   at com.android.build.gradle.internal.tasks.NonIncrementalTask.taskAction(NonIncrementalTask.kt:34)
10:35:36.488 [ERROR] [org.gradle.internal.buildevents.BuildExceptionReporter]   at org.gradle.internal.reflect.JavaMethod.invoke(JavaMethod.java:103)
....

this is my project build.gradle

// Top-level build file where you can add configuration options common to all sub-projects/modules.

buildscript {
    ext.kotlin_version = '1.3.70'
    apply from:'config.gradle'
    repositories {
        google()
        jcenter()


    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.6.1'
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files


//        classpath 'cn.jiguang.android:janalytics-gradle-plugin:3.0.0'

        classpath 'com.meituan.android.walle:plugin:1.1.6'
    }
}

allprojects {
    repositories {
        google()

        jcenter()
        maven { url "https://oss.sonatype.org/content/repositories/snapshots/" }
        maven { url 'http://oss.jfrog.org/artifactory/oss-snapshot-local/' }
        maven { url "https://jitpack.io" }
    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}

and this is my app build.gradle

apply plugin: 'com.android.application'
apply plugin: 'kotlin-android'
apply plugin: 'kotlin-android-extensions'

apply plugin: 'walle'


def dep = rootProject.ext.dependencies
def and = rootProject.ext.android

android {
    compileSdkVersion and.compileSdkVersion
    buildToolsVersion and.buildToolsVersion
    aaptOptions.cruncherEnabled = false

    aaptOptions.useNewCruncher = false
    defaultConfig {
        applicationId and.appid
        minSdkVersion and.minSdkVersion
        targetSdkVersion and.targetSdkVersion
        versionCode 215006
        versionName "3.2"
        multiDexEnabled true
        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"

        ndk {

            abiFilters "armeabi"//, "armeabi-v7a", "arm64-v8a", "x86", "x86_64"
        }
        manifestPlaceholders = [
                JPUSH_PKGNAME : applicationId,
                JPUSH_APPKEY : "94ea05a225c0f9efc3f9e1db", 
                JPUSH_CHANNEL : "developer-default",
        ]
    }
    signingConfigs {
        release {
            keyAlias 'cordova-demo'
            keyPassword ''
            storeFile file('./release-key.keystore')
            storePassword ''
            v1SigningEnabled true
            v2SigningEnabled true

        }

        debug {
            keyAlias 'cordova-demo'
            keyPassword ''
            storeFile file('./release-key.keystore')
            storePassword ''
        }
    }

    buildTypes {
        debug {
            debuggable true
            minifyEnabled false
            signingConfig signingConfigs.debug
            buildConfigField("boolean", "ISRELEASE", "${IS_RELEASE}")
        }
        release {
            debuggable false
            minifyEnabled true
            shrinkResources true /
            zipAlignEnabled true
            signingConfig signingConfigs.release
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
            buildConfigField("boolean", "ISRELEASE", "${IS_RELEASE}")
        }
    }
    sourceSets {
        main {
            jniLibs.srcDirs = ['libs']


        }
    }
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
        encoding = "UTF-8"
    }

    lintOptions {
        abortOnError false
    }
}

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'androidx.appcompat:appcompat:1.1.0'
    implementation 'androidx.constraintlayout:constraintlayout:1.1.3'

    implementation 'junit:junit:4.13'
    androidTestImplementation 'androidx.test:runner:1.2.0'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'


    implementation dep.eventbus
    implementation dep.immersionbar
    implementation dep.immersionbarfragment
    implementation dep.SmartRefreshLayout
//    implementation dep.networking
    implementation project(':android-networking')
//    implementation 'com.amitshekhar.android:jackson-android-networking:1.0.2'
    //glide
    annotationProcessor 'com.github.bumptech.glide:compiler:4.11.0'
    implementation dep.glide
    implementation 'com.github.bumptech.glide:okhttp3-integration:4.9.0'
    implementation 'androidx.annotation:annotation:1.1.0'
    annotationProcessor 'androidx.annotation:annotation:1.1.0'

    implementation dep.rxjava2
    implementation dep.okhttp3
    implementation dep.rxandroid
    implementation dep.rxbinding2
    implementation project(':qmui')
    implementation project(':arch')
    implementation project(':emoji')
    implementation project(':reclib-qq')
    implementation 'com.facebook.stetho:stetho:1.1.1'
    //flowLayout
    implementation(project(':flowlayout-lib')) {
        transitive = true
        exclude group: 'androidx.appcompat', module: 'appcompat'
    }
    implementation dep.multidex
    implementation dep.banner
    implementation dep.toast

    implementation dep.brvah
    implementation dep.gson
    implementation dep.baseadapter
    //webview
    api dep.agentweb
    api 'com.just.agentweb:filechooser:4.1.2'// 
    api 'com.download.library:Downloader:4.1.2'// 

    implementation dep.picker_view

    implementation dep.picker_picture

//    api dep.aliyun

    implementation 'com.amap.api:3dmap:7.0.0'

    implementation 'com.amap.api:location:4.7.2'

    implementation 'com.amap.api:search:6.9.2'
    /**kotlin*/
    implementation "androidx.core:core-ktx:1.2.0"
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
    //utils
    implementation 'com.blankj:utilcode:1.25.9'
    //tablayout//https://github.com/H07000223/FlycoTabLayout
    implementation 'com.flyco.tablayout:FlycoTabLayout_Lib:2.1.2@aar'
    //butter knife
    implementation "com.jakewharton:butterknife:$butterknifeVersion"
    annotationProcessor "com.jakewharton:butterknife-compiler:$butterknifeVersion"


//    api 'com.tencent.mm.opensdk:wechat-sdk-android-without-mta:5.5.7'
    api 'com.tencent.mm.opensdk:wechat-sdk-android-with-mta:5.3.1'


    implementation 'com.yanzhenjie.recyclerview:x:1.3.2'

    implementation 'com.kingja.loadsir:loadsir:1.3.6'
    /*lottie*/
    implementation('com.airbnb.android:lottie:3.2.0') { exclude group: 'com.androidx' }
    implementation 'cn.jiguang.sdk:jmessage:2.9.0'  // 
    implementation 'cn.jiguang.sdk:jcore:2.3.0'  //
    implementation project(':reclib-testemoticons')
    implementation 'cn.jiguang.sdk:jpush:3.5.8'  // 

    implementation 'cn.jiguang.sdk:janalytics:2.1.0' // 

    implementation 'com.github.chrisbanes.photoview:library:1.2.4'
    implementation 'com.github.mtotschnig:StickyListHeaders:2.7.1'
    implementation 'com.michaelpardo:activeandroid:3.1.0-SNAPSHOT'

    implementation 'com.yanzhenjie:permission:2.0.3'

    debugImplementation 'com.didichuxing.doraemonkit:doraemonkit:3.0_beta2'
    releaseImplementation 'com.didichuxing.doraemonkit:doraemonkit-no-op:3.0_beta2'
//    api project(path: ':LibEasyGlide')

    implementation 'com.binioter:guideview:1.0.0'

    implementation 'androidx.legacy:legacy-support-v4:1.0.0'
    //bugly

    implementation 'com.tencent.bugly:crashreport:3.1.7'

    implementation 'com.tencent.bugly:nativecrashreport:3.7.1'


    implementation 'com.meituan.android.walle:library:1.1.6'
    implementation "com.google.android.material:material:$materialVersion"

    api project(path: ':LibEasyGlide')

}

walle {

    apkOutputFolder = new File("${project.buildDir}/outputs/channels");

    apkFileNameFormat = '${appName}-${channel}-${buildType}-v${versionName}.apk';
    //apkFileNameFormat = '${appName}-${packageName}-${channel}-${buildType}-v${versionName}-${versionCode}-${buildTime}.apk';

    channelFile = new File("${project.getProjectDir()}/channel")
}

I suspect it's the problem with proguard-rules.pro but don't know where it is

-optimizationpasses 5

-dontusemixedcaseclassnames

-dontskipnonpubliclibraryclasses

-dontskipnonpubliclibraryclassmembers

-dontpreverify

-verbose

-dontshrink


-keepattributes *Annotation*,InnerClasses

-keepattributes Signature

-keepattributes SourceFile,LineNumberTable

-optimizations !code/simplification/cast,!field/*,!class/merging/*


-dump class_files.txt

-printseeds seeds.txt

-printusage unused.txt

-printmapping mapping.txt


-keep class com.just.agentweb.** {
    *;
}
-dontwarn com.just.agentweb.**
-keepclassmembers class com.yiguan.chuzhu.common.AndroidInterface{ *; }


#glide start
-keep public class * implements com.bumptech.glide.module.GlideModule
-keep public class * extends com.bumptech.glide.module.AppGlideModule
-keep public enum com.bumptech.glide.load.ImageHeaderParser$** {
  **[] $VALUES;
  public *;
}
#glide end


-keep class com.youth.banner.** {
    *;
 }


-keep   class com.amap.api.maps.**{*;}
-keep   class com.autonavi.**{*;}
-keep   class com.amap.api.trace.**{*;}


-keep class com.amap.api.location.**{*;}
-keep class com.amap.api.fence.**{*;}
-keep class com.autonavi.aps.amapapi.model.**{*;}

#utils
-keep class com.blankj.utilcode.** { *; }
-keepclassmembers class com.blankj.utilcode.** { *; }
-dontwarn com.blankj.utilcode.**


-keep public class * extends android.app.Fragment
-keep public class * extends android.app.Activity
-keep public class * extends android.app.Application
-keep public class * extends android.app.Service
-keep public class * extends android.content.BroadcastReceiver
-keep public class * extends android.preference.Preference
-keep public class * extends android.content.ContentProvider
-keep public class * extends android.app.backup.BackupAgentHelper
-keep public class * extends android.preference.Preference
-keep public class * extends android.view.View
-keep public class com.android.vending.licensing.ILicensingService
-keep public class  * extends androidx.appcompat
-keep class androidx.**{*;}


-keep public class * extends android.view.View{
    *** get*();
    void set*(***);
    public <init>(android.content.Context);
    public <init>(android.content.Context, android.util.AttributeSet);
    public <init>(android.content.Context, android.util.AttributeSet, int);
}

-assumenosideeffects class android.util.Log {
    public static *** d(...);
    public static *** v(...);
    public static *** i(...);
    public static *** e(...);
    public static *** w(...);
}

# For enumeration classes, see http://proguard.sourceforge.net/manual/examples.html#enumerations
-keepclassmembers enum * {
    public static **[] values();
    public static ** valueOf(java.lang.String);
}

-keep class * implements android.os.Parcelable {
  public static final android.os.Parcelable$Creator *;
}

-keepclassmembers class **.R$* {
    public static <fields>;
}

-keep public class com.yiguan.chuzhu.R$*{
public static final int *;
}

-keep class * implements java.io.Serializable
-keepclassmembers class * implements java.io.Serializable {
    static final long serialVersionUID;
    private static final java.io.ObjectStreamField[] serialPersistentFields;
    !static !transient <fields>;
    private void writeObject(java.io.ObjectOutputStream);
    private void readObject(java.io.ObjectInputStream);
    java.lang.Object writeReplace();
    java.lang.Object readResolve();
}

-keepclassmembers class fqcn.of.javascript.interface.for.webview {
    public *;
}
-keepclassmembers class * extends android.webkit.webViewClient {
    public void *(android.webkit.WebView, java.lang.String, android.graphics.Bitmap);
    public boolean *(android.webkit.WebView, java.lang.String);
}
-keepclassmembers class * extends android.webkit.webViewClient {
    public void *(android.webkit.webView, jav.lang.String);
}


-keep class * extends com.yiguan.chuzhu.base.BaseModel {*;}


# Keep native methods
-keepclassmembers class * {
    native <methods>;
}

-dontwarn okio.**
-dontwarn com.squareup.okhttp.**
-dontwarn okhttp3.**
-dontwarn javax.annotation.**
-dontwarn com.android.volley.toolbox.**

# Gson
-keepattributes Signature
-keepattributes *Annotation*
-keep class sun.misc.Unsafe { *; }
-keep class com.google.gson.stream.** { *; }

#-keep class com.example.bean.** { *; }

# ButterKnife
-keep public class * implements butterknife.Unbinder {
    public <init>(**, android.view.View);
}
-keep class butterknife.*
-keepclasseswithmembernames class * {
    @butterknife.* <methods>;
}
-keepclasseswithmembernames class * {
    @butterknife.* <fields>;
}


# RxJava RxAndroid
-dontwarn sun.misc.**
-keepclassmembers class rx.internal.util.unsafe.*ArrayQueue*Field* {
    long producerIndex;
    long consumerIndex;
}
-keepclassmembers class rx.internal.util.unsafe.BaseLinkedQueueProducerNodeRef {
    rx.internal.util.atomic.LinkedQueueNode producerNode;
}
-keepclassmembers class rx.internal.util.unsafe.BaseLinkedQueueConsumerNodeRef {
    rx.internal.util.atomic.LinkedQueueNode consumerNode;
}
-dontnote rx.internal.util.PlatformDependent

# keep setters in Views so that animations can still work.
# see http://proguard.sourceforge.net/manual/examples.html#beans
-keepclassmembers public class * extends android.view.View {
   void set*(***);
   *** get*();
}

#evebtbus
-keepattributes *Annotation*
-keepclassmembers class ** {
    @org.greenrobot.eventbus.Subscribe <methods>;
}
-keep enum org.greenrobot.eventbus.ThreadMode { *; }

# Only required if you use AsyncExecutor
-keepclassmembers class * extends org.greenrobot.eventbus.util.ThrowableFailureEvent {
    <init>(java.lang.Throwable);
}

-keep class com.tencent.mm.opensdk.** {
    *;
}

-keep class com.tencent.wxop.** {
    *;
}

-keep class com.tencent.mm.sdk.** {
    *;
}
#loadSir
-dontwarn com.kingja.loadsir.**
-keep class com.kingja.loadsir.** {*;}


-dontoptimize
-dontpreverify
-keepattributes  EnclosingMethod,Signature
-dontwarn cn.jpush.**
-keep class cn.jpush.** { *; }

-dontwarn cn.jiguang.**
-keep class cn.jiguang.** { *; }

-dontwarn cn.jmessage.**
-keep class cn.jmessage.**{ *; }

-keepclassmembers class ** {
    public void onEvent*(**);
}

#========================gson================================
#-dontwarn com.google.**
#-keep class com.google.gson.** {*;}

#========================protobuf================================
-keep class com.google.protobuf.** {*;}

-dontoptimize
-dontpreverify

-dontwarn cn.jpush.**
-keep class cn.jpush.** { *; }
-keep class * extends cn.jpush.android.helpers.JPushMessageReceiver { *; }

-dontwarn cn.jiguang.**
-keep class cn.jiguang.** { *; }


#PictureSelector 2.0
-keep class com.luck.picture.lib.** { *; }

-dontwarn com.yalantis.ucrop**
-keep class com.yalantis.ucrop** { *; }
-keep interface com.yalantis.ucrop** { *; }

# immersionbar
 -keep class com.gyf.immersionbar.* {*;}
 -dontwarn com.gyf.immersionbar.**

#activeandroid
-keep class com.activeandroid.** { *; }
-dontwarn com.ikoding.app.biz.dataobject.**
-dontwarn com.activeandroid.**
-keep public class com.ikoding.app.biz.dataobject.** { *;}
-keepattributes *Annotation*


-keep class cn.jiguang.** { *; }
-keep class android.support.** { *; }
-keep class androidx.** { *; }
-keep class com.google.android.** { *; }

# bugly
-dontwarn com.tencent.bugly.**
-keep public class com.tencent.bugly.**{*;}

It has bothered me for a while, I have been using 3.5.3 now

Answer 1

I solved this by increasing Java heap memory. Add following line to gradle.properties file:

org.gradle.jvmargs=-Xms1024m -Xmx4096m

Note that, this solution works for similar issue, which is : "Out of memory: GC overhead limit exceeded". (These errors are encountered especially while creating release builds)

Answer 2

I tried everything above but didn't work.

Only thing that worked for me was to set

def enableProguardInReleaseBuilds = false

rebuild, then

def enableProguardInReleaseBuilds = true

Don't know why it worked but did.