Error while building the app (cordova build android), after adding and configuring the "cordova-plugin-firebase"

I found a solution to the problem:

Instructions similar to the ones I followed (and that caused the problem) are available here, although with the somewhat outdated versions of the dependencies:

  

link

What caused the problem in my case was to follow these instructions on the application creation page in Firebase and add the dependencies in the build.gradle of project and module files, as can be seen below:

Add file build.gradle of project /project/platforms/android/build.gradle :

buildscript {
    repositories {
        jcenter ()
        maven {
            url "https://maven.google.com"
        }
        Google()
    }
    dependencies {

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
        classpath 'com.android.tools.build:gradle:3.1.3'

        // Firebase
        classpath 'com.google.gms: google-services: 4.0.0'
    }
}

And add to file build.gradle of module /project/platforms/android/app/build.gradle :

buildscript {
    repositories {
        mavenCentral ()
        jcenter ()
        maven {
            url "https://maven.google.com"
        }
        Google()
    }

    dependencies {
        classpath 'com.android.tools.build:gradle:3.1.3'

        // Firebase
        classpath 'com.google.gms: google-services: 4.0.0'
        classpath 'com.google.firebase: firebase-core: 16.0.0'
    }
}

// Firebase, add at the end of the same file
apply plugin: 'com.google.gms.google-services'

Solution:

The solution I found was to comment the lines preceded by the comment // Firebase :

File /project/platforms/android/build.gradle :

buildscript {
    repositories {
        jcenter ()
        maven {
            url "https://maven.google.com"
        }
        Google()
    }
    dependencies {

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
        classpath 'com.android.tools.build:gradle:3.1.3'

        // Firebase
        // classpath 'com.google.gms: google-services: 4.0.0'
    }
}

File /project/platforms/android/app/build.gradle :

    buildscript {
        repositories {
            mavenCentral ()
            jcenter ()
            maven {
                url "https://maven.google.com"
            }
            Google()
        }

        dependencies {
            classpath 'com.android.tools.build:gradle:3.1.3'

            // Firebase
            //classpath 'com.google.gms: google-services: 4.0.0'
            //classpath 'com.google.firebase: firebase-core: 16.0.0'
        }
    }

// Firebase, add at the end of the same file
//apply plugin: 'com.google.gms.google-services'

After these steps, everything worked fine and I was able to run $ cordova build android with no problems.

Tip: If any other error occurs, try removing the plug-ins and platform, then re-create them:

$ cordova plugin rm cordova-plugin-firebase
$ cordova platform rm android

$ cordova plugin add cordova-plugin-firebase
$ cordova platform add android