安卓开发问题之 Unable to instantiate application com.android.tools.fd.runtime.BootstrapApplication

API 21 之前的设备调试，开启Instant run，有可能报这个错，21之后的设备就不会有了，，我这边实践的，应该还是Instant Run 不稳定

所以把instant run 功能取消后在发布测试包就可以。

这个问题出现在程序 Launcher3 运行中，系统端需要我这里修改 Launcher3 的一些东西，修改了给他，出现如下错误：

--------- beginning of /dev/log/main
I/Process ( 1706): Sending signal. PID: 1706 SIG: 9
--------- beginning of /dev/log/system
I/ActivityManager(  731): Process com.inst.launcher3 (pid 1706) has died.
W/art     (  444): Could not get current activity
I/ActivityManager(  731): Start proc com.inst.launcher3 for activity com.inst.launcher3/.Launcher: pid=1729 uid=10034 gids={50034,}
I/art     ( 1729): Failed to open oat file from /system/priv-app/launcher3_INST.odex or /data/dalvik-cache/system@priv-app@launche.
E/art     ( 1729): Failed to open file: /data/dalvik-cache/system@priv-app@launcher3_INST.apk@classes.dex
E/art     ( 1729): Failed to open locked oat file: /data/dalvik-cache/system@priv-app@launcher3_INST.apk@classes.dex
W/art     ( 1729): Failed to open dex file: /system/priv-app/launcher3_INST.apk
D/AndroidRuntime( 1729): Shutting down VM
E/AndroidRuntime( 1729): FATAL EXCEPTION: main
E/AndroidRuntime( 1729): Process: com.inst.launcher3, PID: 1729
E/AndroidRuntime( 1729): java.lang.RuntimeException: Unable to instantiate application com.android.tools.fd.runtime.BootstrapApplication
E/AndroidRuntime( 1729):        at android.app.LoadedApk.makeApplication(LoadedApk.java:516)
E/AndroidRuntime( 1729):        at android.app.ActivityThread.handleBindApplication(ActivityThread.java:4317)
E/AndroidRuntime( 1729):        at android.app.ActivityThread.access$1500(ActivityThread.java:135)
E/AndroidRuntime( 1729):        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
E/AndroidRuntime( 1729):        at android.os.Handler.dispatchMessage(Handler.java:102)
E/AndroidRuntime( 1729):        at android.os.Looper.loop(Looper.java:136)
E/AndroidRuntime( 1729):        at android.app.ActivityThread.main(ActivityThread.java:5017)
E/AndroidRuntime( 1729):        at java.lang.reflect.Method.invoke(Native Method)
E/AndroidRuntime( 1729):        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
E/AndroidRuntime( 1729):        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
E/AndroidRuntime( 1729): Caused by: java.lang.ClassNotFoundException: Didn't find class "com.android.tools.fd.runtime.BootstrapApp]
E/AndroidRuntime( 1729):        at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:56)
E/AndroidRuntime( 1729):        at java.lang.ClassLoader.loadClass(ClassLoader.java:511)
E/AndroidRuntime( 1729):        at java.lang.ClassLoader.loadClass(ClassLoader.java:469)
E/AndroidRuntime( 1729):        at android.app.Instrumentation.newApplication(Instrumentation.java:975)
E/AndroidRuntime( 1729):        at android.app.LoadedApk.makeApplication(LoadedApk.java:511)
E/AndroidRuntime( 1729):        ... 9 more
E/AndroidRuntime( 1729):        Suppressed: java.io.IOException: Unable to open dex file: /system/priv-app/launcher3_INST.apk
E/AndroidRuntime( 1729):                at dalvik.system.DexFile.openDexFileNative(Native Method)
E/AndroidRuntime( 1729):                at dalvik.system.DexFile.openDexFile(DexFile.java:296)
E/AndroidRuntime( 1729):                at dalvik.system.DexFile.(DexFile.java:80)
E/AndroidRuntime( 1729):                at dalvik.system.DexFile.(DexFile.java:59)
E/AndroidRuntime( 1729):                at dalvik.system.DexPathList.loadDexFile(DexPathList.java:263)
E/AndroidRuntime( 1729):                at dalvik.system.DexPathList.makeDexElements(DexPathList.java:230)
E/AndroidRuntime( 1729):                at dalvik.system.DexPathList.(DexPathList.java:112)
E/AndroidRuntime( 1729):                at dalvik.system.BaseDexClassLoader.(BaseDexClassLoader.java:48)
E/AndroidRuntime( 1729):                at dalvik.system.PathClassLoader.(PathClassLoader.java:65)
E/AndroidRuntime( 1729):                at android.app.ApplicationLoaders.getClassLoader(ApplicationLoaders.java:57)
E/AndroidRuntime( 1729):                at android.app.LoadedApk.getClassLoader(LoadedApk.java:326)
E/AndroidRuntime( 1729):                at android.app.LoadedApk.makeApplication(LoadedApk.java:508)
E/AndroidRuntime( 1729):                ... 9 more
E/AndroidRuntime( 1729):        Suppressed: java.lang.ClassNotFoundException: com.android.tools.fd.runtime.BootstrapApplication
E/AndroidRuntime( 1729):                at java.lang.Class.classForName(Native Method)
E/AndroidRuntime( 1729):                at java.lang.BootClassLoader.findClass(ClassLoader.java:781)
E/AndroidRuntime( 1729):                at java.lang.BootClassLoader.loadClass(ClassLoader.java:841)
E/AndroidRuntime( 1729):                at java.lang.ClassLoader.loadClass(ClassLoader.java:504)
E/AndroidRuntime( 1729):                ... 12 more
E/AndroidRuntime( 1729):        Caused by: java.lang.NoClassDefFoundError: Class "Lcom/android/tools/fd/runtime/BootstrapApplicatid
E/AndroidRuntime( 1729):                ... 16 more
W/ActivityManager(  731):   Force finishing activity com.inst.launcher3/.Launcher
W/ActivityManager(  731): Activity pause timeout for ActivityRecord{64d7f5f8 u0 com.inst.launcher3/.Launcher t16 f}

从错误日志里可以看出是：运行时错误，应用不能实例化， google 了下，原来遇到此问题的还不少呢，

Unable to instantiate application com.android.tools.fd.runtime.BootstrapApplication ?Android

解决

---

stackflow上给出的三种解决方法：

1/3:

Changing:

classpath 'com.android.tools.build:gradle:2.0.0-alpha1'
By:

classpath 'com.android.tools.build:gradle:1.2.3'
2/3:

Changing:

buildToolsVersion '23.0.2'
By:

buildToolsVersion "21.1.2"
3/3: (in /.idea/gradle.xml)

And:

By:

我只用了第一个方法就搞定了：
Changing:

classpath 'com.android.tools.build:gradle:2.0.0-beta5'
By:

classpath 'com.android.tools.build:gradle:1.5.0'

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文／追风917（简书作者）
原文链接：http://www.jianshu.com/p/833c97eb8ba7
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