Class not found using the boot class loader; no stack trace available

Question

i got simmilar post but nothing working
i have android studio 2.3.1
gradle version 2.3.1
appcompat-v7:25.3.1

I create a new project by android studio(one that is automatically created by Android Studio(Hello Word)). I haven't write any thing in it.

When i install app using usb via android studio it works perfectly but same app if i open it from it's icon ,i got these errors

One more i noticed that size of apk is 500-600kb ,early it used to be around for hello world(default by android studio) Apk 2.3Mb

FATAL EXCEPTION: main
                                                                     Process: in.codebucket.check, PID: 32397
                                                                     java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{in.codebucket.check/in.codebucket.check.MainActivity}: java.lang.ClassNotFoundException: Didn't find class "in.codebucket.check.MainActivity" on path: DexPathList[[zip file "/data/app/in.codebucket.check-1/base.apk"],nativeLibraryDirectories=[/data/app/in.codebucket.check-1/lib/x86, /vendor/lib, /system/lib]]


      at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2327)
                                                                         at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476)
                                                                         at android.app.ActivityThread.-wrap11(ActivityThread.java)
                                                                         at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344)
                                                                         at android.os.Handler.dispatchMessage(Handler.java:102)
                                                                         at android.os.Looper.loop(Looper.java:148)
                                                                         at android.app.ActivityThread.main(ActivityThread.java:5417)
                                                                         at java.lang.reflect.Method.invoke(Native Method)
                                                                         at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
                                                                         at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
                                                                      Caused by: java.lang.ClassNotFoundException: Didn't find class "in.codebucket.check.MainActivity" on path: DexPathList[[zip file "/data/app/in.codebucket.check-1/base.apk"],nativeLibraryDirectories=[/data/app/in.codebucket.check-1/lib/x86, /vendor/lib, /system/lib]]
                                                                         at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:56)
                                                                         at java.lang.ClassLoader.loadClass(ClassLoader.java:511)
                                                                         at java.lang.ClassLoader.loadClass(ClassLoader.java:469)
                                                                         at android.app.Instrumentation.newActivity(Instrumentation.java:1067)
                                                                         at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2317)
                                                                         at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2476) 
                                                                         at android.app.ActivityThread.-wrap11(ActivityThread.java) 
                                                                         at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344) 
                                                                         at android.os.Handler.dispatchMessage(Handler.java:102) 
                                                                         at android.os.Looper.loop(Looper.java:148) 
                                                                         at android.app.ActivityThread.main(ActivityThread.java:5417) 
                                                                         at java.lang.reflect.Method.invoke(Native Method) 
                                                                         at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726) 
                                                                         at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616) 
                                                                        Suppressed: java.lang.ClassNotFoundException: in.codebucket.check.MainActivity
                                                                         at java.lang.Class.classForName(Native Method)
                                                                         at java.lang.BootClassLoader.findClass(ClassLoader.java:781)
                                                                         at java.lang.BootClassLoader.loadClass(ClassLoader.java:841)
                                                                         at java.lang.ClassLoader.loadClass(ClassLoader.java:504)
                                                                                ... 12 more
                                                                      Caused by: java.lang.NoClassDefFoundError: Class not found using the boot class loader; no stack trace available

    

My xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout   
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="in.codebucket.check.MainActivity">

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Hello World!"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintLeft_toLeftOf="parent"
    app:layout_constraintRight_toRightOf="parent"
    app:layout_constraintTop_toTopOf="parent" />
</android.support.constraint.ConstraintLayout>

My MainActivity

public class MainActivity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
}}

my Manifest

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="in.codebucket.check">

<application

    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:roundIcon="@mipmap/ic_launcher_round"

    android:theme="@style/AppTheme">
    <activity android:name=".MainActivity">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
</application>

</manifest>

gradle(Module:App)

apply plugin: 'com.android.application'

android {
compileSdkVersion 25
buildToolsVersion "25.0.2"
defaultConfig {
    applicationId "in.codebucket.check"
    minSdkVersion 16
    targetSdkVersion 25
    versionCode 1
    versionName "1.0"
    testInstrumentationRunner    "android.support.test.runner.AndroidJUnitRunner"
 }
buildTypes {
    release {
        minifyEnabled false
        proguardFiles getDefaultProguardFile('proguard-android.txt'), 
    'proguard-rules.pro'
    }}}

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:appcompat-v7:25.3.1'
compile 'com.android.support.constraint:constraint-layout:1.0.2'
testCompile 'junit:junit:4.12'
}

gradle(Project)

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

buildscript {
repositories {
    jcenter()
}
dependencies {
    classpath 'com.android.tools.build:gradle:2.3.1'

    // NOTE: Do not place your application dependencies here; they belong
    // in the individual module build.gradle files
}
}

allprojects {
repositories {
    jcenter()
}
}

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

Answer 1

Got the solution ,it is happening because of instant run, Just disable it

Goto :

Android Studio --> File --> Setting --> Build, execution, deploy -->  Instant run.

Answer 2

No need to disable instant run, just remove the app from device/emulator and clean the project and install it again.