title: Program type already present: okhttp3.Call$Factory
body: <p>I have a very simple Android project that refuses to build in Android Studio and just gives me this cryptic error message:</p>
  
  <pre><code>Program type already present: okhttp3.Call$Factory
  Message{kind=ERROR, text=Program type already present: okhttp3.Call$Factory, sources=[Unknown source file], tool name=Optional.of(D8)}
  </code></pre>
  
  <p>Here are my dependencies:</p>
  
  <pre><code>dependencies {
      implementation fileTree(include: ['*.jar'], dir: 'libs')
      implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
      implementation 'com.android.support:appcompat-v7:27.1.0'
      implementation 'com.android.support.constraint:constraint-layout:1.0.2'
      implementation 'net.openid:appauth:0.7.0'
      implementation 'com.squareup.okhttp3:okhttp:3.10.0'
      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 files('libs/easywsdl/ksoap2-android-assembly-3.6.2-jar-with-dependencies.jar')
      implementation files('libs/easywsdl/ExKsoap2-1.0.2.0.jar')
  }
  </code></pre>
  
  <p>How can I troubleshoot that?</p>