Android Studio: Failed to load dx.jar-ThrowExceptions

Exception or error:

When I run my module in Android Studio I get this error:

Error:Android Dex: [GradleDevBuild] Failed to load dx.jar

I have searched endlessly for a solution online but everything is related to eclipse, there is nothing when it comes to Android Studio.

The path to the dex.jar is C:\AndroidSdk\build-tools\26.0.0\lib\dex.jar
So it does exists, I’ve moved it out of the folder and was notified that it moved so AS is aware of where it is. I have tried copying it into the root directory and into the platform-tools folder however that did nothing.

This is the full list of errors that all seem to be stemming from this dx.jar error.

Error:Android Dex: [GradleDevBuild] Failed to load dx.jar
Error:Android Dex: [GradleDevBuild] java.lang.ClassNotFoundException:
Error:Android Dex: [GradleDevBuild] at
Error:Android Dex: [GradleDevBuild] at java.lang.ClassLoader.loadClass(
Error:Android Dex: [GradleDevBuild] at java.lang.ClassLoader.loadClass(
Error:Android Dex: [GradleDevBuild] at
Error:Android Dex: [GradleDevBuild] at
Error:Android Dex: [GradleDevBuild] at
Error:Android Dex: [GradleDevBuild] Exception in thread "main" java.lang.NullPointerException
Error:Android Dex: [GradleDevBuild] at
How to solve:

I just clean installed Android Studio on OS X and Ubuntu and had the same issue. Fixed by downgrading the build tools to 25.0.3.

For @emjapeve:

  • Select the SDK Manager (Tools/Android/SDK Manager).
  • Hit the SDK Tools tab, by default this only shows current tool versions.
  • Select the Show Package Details checkbox.

From here you can install / uninstall any versions you wish.


If you are doing a Legacy build then here is the fix …

Android Build Tools when used by Android Studio can produces a dx.jar error during dexing.

Please revert the Android Build Tools to 25.0.3.

Tools->Android->SDK Manager
    Click on SDK Tools
    Check the Show Package Details Box in the Lower Right
    Unselect Android SDK Build Tools 26 or higher
    Select Android SDK Build Tools 25.0.3


My fix is to copy


to the folder


Now all works great with Eclipse


In my case I copied the dx.jar file from pathToYourSDK/build-tools/25.0.1/lib to pathToYourSDK/build-tools/25.0.1/ and it worked.


In sdk manager do the following
In my case my
1. Android SDK tools version was 25.2.5
2. Android SDK platform tools version was 26
3. Android SDK Build tools version was 26.0.1

Deleted 3
Android SDK Build tools version 25.0.3
Problem solved
You can download and delete corresponding version of package according to your sdk tools version


My case:
IntelliJ IDEA,
libgdx – project

In my case my Project was not configured for gradle yet after opening it for the first time. I restarted my IDE and clicked on the “configure gradle” Pop-up on the lower right site and it worked.

see this Thread:
Module … is not backed by gradle


No need to uninstall build tools ‘normally’. Just enough to go to the …/Sdk/build-tools/ and rename and chmod 000 all the folders for tools older than 24.x.x or 25.x.x (recovered as quickly when needed back)

(had this problem playing with rmaps (ancient project compiled in times of froyo with Eclipse) )


With the new Eclipse update, the Android SDK’s that are above 25.0.0 are making problems (with the lib\dex.jar) and you can’t run the project if you have other SDK’s in the same build-tools folder, cause the Eclipse will preselect the latest SDK and you can’t switch to 25.0.0. Just remove the SDK’s that are above 25 in the folder.

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