java lang RuntimeException Unable to instantiate activity ComponentInfo

Question

I was trying to run a sample code  While launching the application in the android 1 5 emulator   I got these errors     Any one have some hint     ERROR from LogCat   01-13 02 28 08 392  ERROR AndroidRuntime 2888   FATAL EXCEPTION  main 01-13 02 28 08 392  ERROR AndroidRuntime 2888   java lang RuntimeException  Unable to instantiate activity ComponentInfo com s android test com s android test MainActivity   java lang ClassNotFoundException  com s android test MainActivity in loader dalvik system PathClassLoader  data app com s android test-2 apk  01-13 02 28 08 392  ERROR AndroidRuntime 2888       at android app ActivityThread performLaunchActivity ActivityThread java 1544  01-13 02 28 08 392  ERROR AndroidRuntime 2888       at android app ActivityThread handleLaunchActivity ActivityThread java 1638  01-13 02 28 08 392  ERROR AndroidRuntime 2888       at android app ActivityThread access 1500 ActivityThread java 117  01-13 02 28 08 392  ERROR AndroidRuntime 2888       at android app ActivityThread H handleMessage ActivityThread java 928  01-13 02 28 08 392  ERROR AndroidRuntime 2888       at android os Handler dispatchMessage Handler java 99  01-13 02 28 08 392  ERROR AndroidRuntime 2888       at android os Looper loop Looper java 123  01-13 02 28 08 392  ERROR AndroidRuntime 2888       at android app ActivityThread main ActivityThread java 3647  01-13 02 28 08 392  ERROR AndroidRuntime 2888       at java lang reflect Method invokeNative Native Method  01-13 02 28 08 392  ERROR AndroidRuntime 2888       at java lang reflect Method invoke Method java 507  01-13 02 28 08 392  ERROR AndroidRuntime 2888       at com android internal os ZygoteInit MethodAndArgsCaller run ZygoteInit java 839  01-13 02 28 08 392  ERROR AndroidRuntime 2888       at com android internal os ZygoteInit main ZygoteInit java 597  01-13 02 28 08 392  ERROR AndroidRuntime 2888       at dalvik system NativeStart main Native Method  01-13 02 28 08 392  ERROR AndroidRuntime 2888   Caused by  java lang ClassNotFoundException  com s android test MainActivity in loader dalvik system PathClassLoader  data app com s android test-2 apk  01-13 02 28 08 392  ERROR AndroidRuntime 2888       at dalvik system PathClassLoader findClass PathClassLoader java 240  01-13 02 28 08 392  ERROR AndroidRuntime 2888       at java lang ClassLoader loadClass ClassLoader java 551  01-13 02 28 08 392  ERROR AndroidRuntime 2888       at java lang ClassLoader loadClass ClassLoader java 511  01-13 02 28 08 392  ERROR AndroidRuntime 2888       at android app Instrumentation newActivity Instrumentation java 1021  01-13 02 28 08 392  ERROR AndroidRuntime 2888       at android app ActivityThread performLaunchActivity ActivityThread java 1536  01-13 02 28 08 392  ERROR AndroidRuntime 2888           11 more 01-13 02 28 08 407  WARN ActivityManager 112     Force finishing activity com s android test  MainActivity   Edit This error happens to most of the beginners  the thing is that you have to add all your activities in the Manifest file

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As suggested by djjeck in comment in this answer I missed to put public modifier for my class   It should be  public class MyActivity extends AppCompatActivity     It may help some like me

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I have tried all above solution but nothing work for me  after I have just add extend activity instead of AppCompatActivity and working fine   used  public class MainActivity extends Activity     instead of  public class MainActivity extends AppCompatActivity    i dont know what real issue was that

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Ok  I am fairly experienced on the iPhone but new to android  I got this issue when I had   Button infoButton    Button findViewById R id InfoButton     this line of code above    Override public void onCreate  Bundle savedInstanceState        May be I am sleep deprived  P

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Also if you re retrieving something from intent of another activity using getIntent in the current activity and setting those retrieved data before above onCreate then this exception is thrown   For eg  if i retrieve a string like this   final String slot1   getIntent   getExtras   getString  Slot1      and put this line of code before above onCreate then this exception is thrown

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This error also occurs when you use of ActionBarActivity but assigned a non AppCompat style    To fix this just set your apps style parent to an Theme AppCompat one like this     lt  -- Base application theme  -- gt   lt style name  AppTheme  parent  Theme AppCompat Light  gt       lt  -- Customize your theme here  -- gt   lt  style gt

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This can also happen if you have two projects with the same package name and you ran one of them before the other so I guess it confuses Eclipse  For me this happened when I copied an Android tutorial in eclipse in the same workspace and left the package names the same but added ActionBarSherlock  ABS  to it  e g    package  com example android whatever    So in my AndroidManifest xml file  both the tutorial project that was in my workspace and the copied tutorial project both had as the package string    lt manifest xmlns android  http   schemas android com apk res android      package  com example android whatever             lt  manifest gt    Just change the package name by refactoring  In eclipse  right click on package in Package Explorer tab   select Refractor   select Rename     and then changing it in your AndroidManifest xml file and anywhere else you need to  e g  like all your  java files

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This can happen if your activity class is inside a default package  I fixed it by moving the activity class to a new package  and changing the manifest xml  before  activity android name   MainActivity     after  activity android name  new package MainActivity

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It also happens because of this issue  I unchecked the jars that needed be exported to the apk and this same thing happened  Please tick the jars that your app Needs to run

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Simply Clean your working project or restart eclipse  Then run your project  it will work

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Whow are there lots of ways to get this error   I will add another given none of the others either applied  or were the cause  I forgot the  public  in the declaration of my activity class  It was package private  I had been writing so much Bluetooth code that habit caused me to create an activity class that was package private  Says something about the obscurity of this error message

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In my case  I had to add a new Android 6 0 Library by going to Window    Preferences    Java    Build Path    User Libraries    Add Library    User Library    New  Name it Android 6 0  then click OK  After that  add the android jar file that you can find in  sdklocation platforms android-23 android jar   Make sure you do all this in the Android project

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If you have Android Studio 2 3 3 and Android Studio 3 0 0 installed  then switching between the two programs for development will cause this error  This is because there exist situations where classes supported in one program is not supported by the other and vice versa  It is important to maintain consistency in  which version of Android Studio is being used to develop a project

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In my case I forget to make MainActivity class as public  Other solutions   Add activity in Manifest file  Verify all access modifiers

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In my case I haven t set the setContentView R layout main    If you create a new class do not foget to set this in on onCreate Bundle savedInstanceState  method   I have done this stupid mistake several times

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Right click on project   properties   android   and try with different version of the android earlier i was doing with android 4 4 then i changed to android 4 3 and it worked

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you may have some errors in your fields like   public class Search costumer extends Activity       you may have some errors like this  int x  3 0     I have error in initializing this variable too   MySimpleOnGestureListener mySimpleOnGestureListener  new MySimpleOnGestureListener     public void onCreate Bundle savedInstanceState            super onCreate savedInstanceState         so my advice is to perform all initialization in onCreate method not directly in your fields   solve like that   public class Search costumer extends Activity    public void onCreate Bundle savedInstanceState            super onCreate savedInstanceState       you may have some errors like this  int x  3 0     I have error in initializing this variable too   MySimpleOnGestureListener mySimpleOnGestureListener  new MySimpleOnGestureListener

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Sometimes isMinifyEnabled   false may help  make sure you clean the project before launch

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In my case I had two version of  android-support-v4 jar  references in the project   After resolving this  removed additional incorrect reference  solved the issue

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You may be trying to find the view before onCreate   which is incorrect   public class MainActivity extends Activity      ImageView mainImage    ImageView  findViewById R id imageViewMain     incorrect     Override   protected void onCreate Bundle savedInstanceState       super onCreate savedInstanceState       setContentView R layout activity main

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This also happens when you type the wrong applicationId in the build gradle file   For eg  Your application ID is com example myapp app  And you wrote build gradle file like this   android       compileSdkVersion 23     buildToolsVersion  23 0 1       defaultConfig           applicationId  com example myapp            this will make your app crash so write exact applicationId as it is         minSdkVersion 8         targetSdkVersion 8

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Your New Activity add AndroidManifest xml like   NewActivity     lt  activity gt               lt activity android name   NewActivity    gt

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This happened to me when I tried to run an Activity on 2 2 that used imports from Honeycomb not available in older versions of Android and not included in the v4 support package either

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I encountered this problem too  but in a slightly different way   Here was my scenario   App detail    Using ActionBarSherlock as a library Using android-support-v4-r7-googlemaps jar in the ActionBarSherlock library so I could use a  map fragment  in my primary project Added the jar to the build path of my primary project Included the  lt uses-library android name  com google android maps    gt  in the manifests of both the library project and my primary project  this may not be necessary in the library   The manifest in the primary project had the proper activity definition and all of the appropriate properties I didn t have an abstract activity or any of the other gotchas I ve seen on Stack Overflow pertaining to this problem    However  I still encountered the error described in the original post and could not get it to go away   The problem though  was slightly different in one regard    It only affected a fresh install of the application to my device   Any time the app installed for the first time  I would get the error preceded by several  warnings  of  Unable to resolve superclass of FragmentActivity Those warnings traced back to the ActionBarSherlock library The app would force close and crash  If I immediately rebuilt and redeployed the app  it worked fine   The only time it crashed was on a totally fresh install   If I uninstalled the app  built and deployed again from Eclipse  it would crash   Build deploy a second time  it would work fine    How I fixed it    In the ActionBarSherlock library project  I added the android-support-v4-r7-googlemaps jar to the build path This step alone did not fix the problem Once the jar was added to the build path  I had change the order on the Java Build Path   Order and Export tab - I set the JAR to the first item in the list  it was the last after the  src and  gen items   I then rebuilt and redeployed the app to my device - it worked as expected on a fresh install   Just to be certain  I uninstalled it again 2-3 times and reinstalled - still worked as expected    This may be a total rookie mistake  but I spent quite a while digging through posts and my code to figure it out  so hopefully it can be helpful to someone else   May not fix all situations  but in this particular case  that ended up being the solution to my problem

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Most the time If Activity name changed reflected all over the project except the AndroidManifest xml file    You just need to Add the name in manifest manually    lt activity android name  Activity Class Name  android label   string app name  gt   lt  activity gt

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It is a problem of your Intent   Please add your Activity in your  AndroidManifest xml   When you want to make a new activity  you should register it in your AndroidManifest xml

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My problem was missing package declaration in the beginning of the activity source file  package com my package

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Don t do like this  ImageView imageView findViewById R id imageView    Override protected void onCreate Bundle savedInstanceState        super onCreate savedInstanceState       setContentView R layout activity main     Do it like this   ImageView imageView   Override protected void onCreate Bundle savedInstanceState        super onCreate savedInstanceState       setContentView R layout activity main       imageView findViewById R id imageView

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Got this problem  and fixed it by setting the  launch mode  property of the activity

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Another reason of this problem may be a missing library   Go to Properties -  Android and check that you add the libraries correctly

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This might not be relevant to the actual question  but in my instance  I tried to implement Kotlin and left out apply plugin   kotlin-android   The error happened because it could not recognize the MainActivity in as a  kt file   Hope it helps someone

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You should make sure that all the activities in your application are properly defined in the AndroidManifest xml file   Also  if they start with a path make sure this path exists   E g  this will not work    lt activity android name   com example android networkusage NetworkActivity  android label   string app name   gt    If your application s name is com example networkusage  note the missing  android    Or better yet  don t include paths when defining an activity inside the manifest  Only put their name  with a dot in front of it     lt activity android name   NetworkActivity  android label   string app name   gt

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In my case I forgot to add the google maps library   lt application gt                 lt uses-library android name  com google android maps    gt   lt  application gt    Also  check that you re not missing the preceding dot before the activity path   lt activity android name   activities MainActivity   gt

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I got rid of this problem by deleting the Bin and Gen folder from project which automatically come back when the project will build  and then cleaning the project from - Menu -  Project -  clean   Thanks

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This happens to me fairly frequently when using the NDK  I found that it is necessary for me to do a  Clean  in Eclipse after every time I do a ndk-build  Hope it helps anyone

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In my case  I was trying to embed the Facebook SDK and I was having the wrong Application ID  thus the error was popping up  In your manifest file  you should have the proper meta data    lt meta-data android name  com facebook sdk ApplicationId  android value   string facebook app id    gt

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For me  my package string in AndroidManifest xml was incorrect  copied from a tutorial   Make sure the package string in this file is the same as where your main activity is  e g    package  com example app    An easy way to do this is to open the AndroidManifest xml file in the  Manifest  tab  and type it in the text box next to Package  or use the Browse button   Also  the package string for my activity was wrong  e g    lt activity android name  com example app MainActivity  android label   string app name  gt    I  stupidly  got the same error weeks later when I renamed my package name   If you do this  make sure you update the AndroidManifest xml file too

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For me it was different from any of the above   The activity was declared as abstract  That is why giving the error   Once it removed it worked   Earlier       public abstract class SampleActivity extends AppcompatActivity           After removal       public class SampleActivity extends AppcompatActivity

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I had the same issue  Unable to instantiate Activity     FIRST reason     I was accessing  Camera mCamera  Camera Parameters params   mCamera getParameters      before   mCamera   Camera open      So right way of doing is  open the camera first and then access parameters    SECOND reason   Declare your activity in the manifest file    lt activity android name   activities MainActivity   gt    THIRD reason    Declare Camera permission in your manifest file    lt uses-feature android name  android hardware Camera  gt  lt  uses-feature gt   lt uses-permission android name  android permission CAMERA    gt    Hope this helps

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I had the same problem  but I had my activity declared in the Manifest file  with the correct name   My problem was that I didn t have to imported a third party libraries in a  libs  folder  and I needed reference them in my proyect  Right-click  properties  Java Build Path  Libraries  Add Jar

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There is another way to get an java lang RuntimeException  Unable to instantiate activity ComponentInfo exception and that is the activity that you are trying to start is abstract  I made this stupid mistake once and its very easy to overlook

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I recently encountered this with fresh re-install of Eclipse  Turns out my Compiler compliance level was set to Java 1 7 and project required 1 6   In Eclipse  Project -  Properties -  Java Compiler -  JDK Compliance

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In my case  I was trying to initialize the components UI  even before the onCreate is called for the Activity   Make sure your UI components are initialized linked in the onCreate method after setContentView  NB  This is my first mistake while learning Android programming

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This error can also be the ultimate sign of a dumb mistake  like when I - I mean  cough  like when a friend of mine who showed me their code once  where they try to execute code outside of a method like trying to do this   SQLiteDatabase db   openOrCreateDatabase  DB   MODE PRIVATE  null     trying to perform function where you can only set up objects  primitives  etc   Override public void onCreate Bundle savedInstanceState             rather than this   SQLiteDatabase db    Override public void onCreate Bundle savedInstanceState    db   openOrCreateDatabase  DB   MODE PRIVATE  null

[android] java.lang.RuntimeException: Unable to instantiate activity ComponentInfo

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