error: package com.android.annotations does not ex

Question

I have the following class

import com.android.annotations.NonNullByDefault;

@NonNullByDefault
public final class Log {
    ...
}

and here is my build.gradle file (some parts omitted)

apply plugin: 'com.android.application'

android {
    compileSdkVersion 25
    buildToolsVersion '24.0.1'

    defaultConfig {
        minSdkVersion 16
        targetSdkVersion 25
        versionCode 2
        versionName "0.2"
    }

    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_7
        targetCompatibility JavaVersion.VERSION_1_7
    }

}

dependencies {    
    compile 'com.android.support:appcompat-v7:25.0.0'
    compile 'com.android.support:support-annotations:25.0.0'
    compile 'com.android.support:design:25.0.0'
}

In Android Studio there is no warning raised for my class

However when I try to build and run my app I get this error from gradle

Information:Gradle tasks [:app:clean, :app:generateDebugSources, :app:generateDebugAndroidTestSources, :app:mockableAndroidJar, :app:prepareDebugUnitTestDependencies, :app:assembleDebug]
Warning:[options] bootstrap class path not set in conjunction with -source 1.7
/home/puter/git-repos/TaskManager3/app/src/main/java/com/treemetrics/taskmanager3/util/Log.java
Error:(3, 31) error: package com.android.annotations does not exist
Error:(7, 2) error: cannot find symbol class NonNullByDefault
Error:Execution failed for task ':app:compileDebugJavaWithJavac'.
> Compilation failed; see the compiler error output for details.
Information:BUILD FAILED
Information:Total time: 21.021 secs
Information:3 errors
Information:1 warning
Information:See complete output in console

Answer 1

You can find here the official javadoc of the support-annotationslibrary.

Error:(3, 31) error: package com.android.annotations does not exist

As you can see all the classes are in the same package android.support.annotation and not com.android.annotations.

Error:(7, 2) error: cannot find symbol class NonNullByDefault

Also the class NonNullByDefault doesn't exist in that package.

Answer 2

Open gradle.properties and use following code:

android.useAndroidX=false
android.enableJetifier=false

or U can use these dependencies too:

implementation 'androidx.appcompat:appcompat:1.0.2'
 implementation 'androidx.annotation:annotation:1.0.2'

Answer 3

Annotations come from the support's library which are packaged in android.support.annotation.

As another option you can use @NonNull annotation which denotes that a parameter, field or method return value can never be null.
It is imported from import android.support.annotation.NonNull;

Answer 4

Use implementation androidx.appcompat:appcompat:1.0.2 in gradle and then

change import android.support.annotation.Nullable; to import androidx.annotation.NonNull; in the classes imports

Answer 5

In my case I had to use

import androidx.annotation...

instead of

import android.annotation...

I migrated to AndroidX and forgot to change that.