importing NotNull or Nullable and Android Studio won't compile

Question

When I add @NotNull or @Nullable annotations to a parameter Android Studio automatically helps me with adding /lib/annotations.jar and importing

import org.jetbrains.annotations.NotNull
import org.jetbrains.annotations.Nullable;

But after this, the project won't compile. If I also remove the annotations but keep the import statements the project still won't compile. But if I remove the import statements for NotNull and Nullable the project compiles fine!

Android Studio gives a generic error:

Gradle: 
FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':Bugtester:compileDebug'.
> Compilation failed; see the compiler error output for details.

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.

Running gradlew compileDebug from cmd gives a slight hint:

:Bugtester:compileDebug FAILED

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':Bugtester:compileDebug'.
> Cannot find System Java Compiler. Ensure that you have installed a JDK (not just a JRE) and configured your JAVA_HOME system variable to point to the according directory.

* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output.

BUILD FAILED

So I checked my environment variables and they are set as:

JAVA_HOME=C:\Program Files (x86)\Java\jre7
JDK_HOME=C:\Program Files\Java\jdk1.7.0_21\

Anyone got any idea for this? (I'm new to both java and android programming)

I'm not familiar with gradle, but you should probably add a dependency on `annotations.jar` to `build.gradle`. Something like `dependencies { compile files('full/path/to/annotations.jar') }` — Vladimir Mironov, May 22 '13 at 12:04
Thanks, this fixed the issue! I thought adding the dependency was what android studio did automatically when I first wrote @NotNull and it wanted me to add something. — Moberg, May 22 '13 at 12:44
You can find explanation for this behavior here http://stackoverflow.com/questions/16622410/how-do-i-add-a-library-project-to-the-android-studio-and-use-itsome-asked-dont/16683375#16683375 — Vladimir Mironov, May 22 '13 at 12:54

score 83 · Accepted Answer · edited Jan 18 '20 at 07:47

83

I guess, the right way is using original JetBrains library from MavenCentral repository in your build.gradle dependencies (latest available version in this example):

dependencies {
    implementation 'com.intellij:annotations:+@jar'
    ...
}

edited Jan 18 '20 at 07:47

Maifee Ul Asad

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answered Dec 08 '13 at 17:08

Serge Populov

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`implementation` is used instead of `compile` in newer versions – Diblo Dk Apr 25 '18 at 19:38
3

I use implementation 'org.jetbrains:annotations:16.0.2' -- for gradle-5.1.1, its works for me. – Mahmudur Rahman May 06 '19 at 10:20
Complete newb here -> Android 4, this did not work for me even after resync gradle and rebuild project. I still get red errors. – Dean Hiller Jul 25 '20 at 01:35
removing this Line implementation 'org.jetbrains:annotations:15.0' from my build.gradle file solved my problem. – Aqeel Mughal Jul 12 '21 at 10:32

score 49 · Answer 2 · answered Sep 11 '14 at 13:04

49

You can also use android's own @NonNull & @Nullable:

Add the following to build.gradle:

dependencies {
    ...
    // For @Nullable/@NonNull
    compile 'com.android.support:support-annotations:+'
}

Go to File / Setting → Project Settings → Inspections and search for "nullable".

In Constant conditions & exceptions and @NotNull/@Nullable problems, click Configure annotations and select Android's annotations.

You may also want to check out Suggest @Nullable annotations… under Constant conditions & exceptions, or possibly tweak other options.

answered Sep 11 '14 at 13:04

squirrel

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Your answer has solved my problem. Just one thing: The "Avoid using + in version number" warning is shown... i have set my version like this: `compile 'com.android.support:support-annotations:23.1.1'` – Primoz990 Nov 26 '15 at 09:26
Was that supposed to be on Mac Android Studio -> Preferences, but then I can't find Project Settings nor Inspections. I am on Android Studio 4. – Dean Hiller Jul 25 '20 at 01:36

score 13 · Answer 3 · edited Oct 07 '16 at 16:49

For using Android support anotation like - @Nullable, @NonNull etc.. In your project must be imported android support annotations library. Just add this line to dependensies in gradle file

dependencies { compile 'com.android.support:support-annotations:+' }

And import package to class.
For using @Nullable annotation:

import android.support.annotation.Nullable;

For @NonNull

import android.support.annotation.NonNull;

More info you can find here Android developers

Xavier Ducrohet · Answer 4 · 2013-11-26T22:02:34.723

At the moment, there is no NonNull/Nullable annotations in the Android API or in the support library. You also cannot use the IntelliJ one since they are not on the compilation classpath when building with Gradle.

However, you can easily create your own. It's very simple:

@Documented
@Retention(RetentionPolicy.CLASS)
@Target({METHOD,PARAMETER,LOCAL_VARIABLE,FIELD})
public @interface NonNull {
}

Once this is down, you can configure IntelliJ (or Android Studio) to recognize this one (and the matching @Nullable) to be the default annotation used for Null-checks.

To do this, go in the IntelliJ preferences, under Inpections, and then find the @NotNull/@Nullable problems entry under Probable Bugs in the inspection tree.

Select the item, and in the bottom right you'll have a button to "Configure Annotations". This will allow you set your own annotations as the one intelliJ will use for this inspection.

upvote because this tip does not need any additional third party libraries — Dominik Obermaier, Dec 22 '14 at 14:43

score 6 · Answer 5 · answered Jan 21 '21 at 16:31

6

Just import androidx.annotation.Nullable for that purpose

answered Jan 21 '21 at 16:31

Azizjan Hamidovich Ayupov

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Thanks! As of today, this is the easiest change – Nagabhushan S N Jul 04 '21 at 06:03
Not sure whether it's easier than other options but it seems to be the best today; the current way the functionality is exposed. And need to add to build.gradle dependencies "implementation 'androidx.annotation:annotation:1.6.0'" or something like that. – steve Apr 14 '23 at 17:43

Amio.io · Answer 6 · 2019-04-28T15:56:22.570

5

In 2015, you would have used annotations from android.support.annotation package. I am just not sure when they added them as in the docs there isn't that typical sentence "Added in API level X" and I don't feel like reading blogs, etc. >]

import android.support.annotation.NonNull;

...

public void fooFighter(@NonNull Object honeyBunny){
   ...
}

edited Apr 28 '19 at 15:56

answered May 16 '15 at 07:54

Amio.io

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Gone are the nowadays of 2015, in the nowadays of 2019, use **androidx.annotation:annotation:1.x.x** :P – varun Apr 27 '19 at 10:32
_Smoooooooth!_ +1 ;) – varun Apr 28 '19 at 16:31

score 4 · Answer 7 · answered May 06 '19 at 10:32

4

I am facing that problem for gradle-5.1.1 - Android Studio 3.4 and the error like that - Compilation failed; see the compiler error output for details. Execution failed for task ':app:compileDebugJavaWithJavac'. etc. In this case I use

implementation 'org.jetbrains:annotations:16.0.2'

and above all error will be clear.

answered May 06 '19 at 10:32

Mahmudur Rahman

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I wish this worked. But like everything else, I can't seem to shake this error. – SMBiggs Jun 12 '19 at 05:53

score 0 · Answer 8 · edited Jun 05 '14 at 14:56

0

The best way is to use the maven dependency

set the repository path, by adding

repositories {
    maven {
        url "https://repository.jboss.org/nexus/content/repositories/thirdparty-releases"
    }
}

add the dependency

dependencies {
    compile 'org.jetbrains:annotations:7.0.2'
}

PROFIT!

edited Jun 05 '14 at 14:56

respectTheCode

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answered Dec 08 '13 at 11:34

curioushikhov

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score 0 · Answer 9 · answered Jun 13 '19 at 11:17

0

For Maven add dependency:

<dependency>
    <groupId>org.jetbrains</groupId>
    <artifactId>annotations</artifactId>
    <version>16.0.1</version>
</dependency>

answered Jun 13 '19 at 11:17

DeadCoon

81
4

importing NotNull or Nullable and Android Studio won't compile

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