Is there a NonNullByDefault annotation for Android Studio

Question

I am really missing @NonNullByDefault from eclipse in Android Studio. Is there a way to get this or something similar? I only saw one using javax's @TypeQualifierDefault, but this seems not to be available in the android project.

Answer 1

You can actually just add the eclipse annotation package to your project and use it.

Simply add

dependencies {
    implementation group: 'org.eclipse.jdt', name: 'org.eclipse.jdt.annotation', version: '2.2.600'
}

To your gradle and you can use the @NonNullByDefault annotations it provides.

As usual you can either set it per class

@NonNullByDefault
public class MyClass {
    String test = "This is a non null string"
    @Nullable test2 = "This is a nullable string"

    public MyClass(String nonNullParam, @Nullable String nullableParam) {
        Object nonNullVar = nonNullParam;
        @Nullable Object nullableVar = nullableParam;
    }
}

Or you can set it for an entire package by creating a package-info.java file and in it

@NonNullByDefault   
package my.package;

import org.eclipse.jdt.annotation.NonNullByDefault;

You still need to activate the setting in https://stackoverflow.com/a/35942944/2075537 to have complete coverage in case you forget it on a package