android - What does "Program type already present" mean?

Question

I'm trying to build an app in Android Studio. After adding the Eclipse Paho library as a gradle dependency(or is it Maven? I'm new to the Android ecosystem), I got the following error:

Program type already present: android.support.v4.accessibilityservice.AccessibilityServiceInfoCompat
Message{kind=ERROR, text=Program type already present: android.support.v4.accessibilityservice.AccessibilityServiceInfoCompat, sources=[Unknown source file], tool name=Optional.of(D8)}

I've checked many different StackOverflow questions relating to this error, but the answers are all specific to certain libraries. I'm looking not only for a solution to the error, but an understanding of what the error means. That way it'll be easier for people to figure out solutions for their specific cases. So far, no answer has provided that.

From other StackOverflow answers, I've gathered that it has something to do with my gradle file. So, here's app/build.gradle:

apply plugin: 'com.android.application'
android {
    compileSdkVersion 27
    defaultConfig {
        applicationId "---REDACTED FOR PRIVACY---"
        minSdkVersion 15
        targetSdkVersion 27
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}
dependencies {
    implementation fileTree(include: ['*.jar'], dir: 'libs')
    implementation 'com.android.support:appcompat-v7:27.1.0'
    implementation 'com.android.support:support-media-compat:27.1.0'
    implementation 'com.android.support:support-v13:27.1.0'
    implementation 'com.google.android.gms:play-services-maps:12.0.1'
    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'com.android.support.test:runner:1.0.1'
    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.1'
    implementation 'com.android.support.constraint:constraint-layout:1.0.2'
    implementation 'org.eclipse.paho:org.eclipse.paho.client.mqttv3:1.0.2'
    implementation 'org.eclipse.paho:org.eclipse.paho.android.service:1.0.2'
}

repositories {
    maven { url 'https://repo.eclipse.org/content/repositories/paho-releases/' }
} 

Answer 1

For me just cleaning the project solved the issue

Using Terminal :

./gradlew clean

Using Android Studio :

Build (menu) > Clean Project