title: Why do I have different versions of Kotlin JARs in the classpath?
body: <p>I decided to add a couple Kotlin files to an existing Java Android project in AS 3.0.</p>
  
  <p>Once I added Kotlin files, I let the assistant add the appropriate lines to my <code>build.gradle</code> files, in particular:</p>
  
  <p><code>project build.gradle</code></p>
  
  <pre><code>buildscript {
      ext.kotlin_version = '1.2.21'
      //...
      dependencies {
          classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
  </code></pre>
  
  <p><code>app build.gradle</code></p>
  
  <pre><code>// top of file
  apply plugin: 'com.android.application'
  apply plugin: 'kotlin-android'
  //....
  dependencies {
      compile "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
  </code></pre>
  
  <p>Unfortunately all builds now produce this warning:</p>
  
  <pre><code>Warning:Runtime JAR files in the classpath should have the same version. These files were found in the classpath:
  /Users/sddsfsd/.gradle/caches/modules-2/files-2.1/org.jetbrains.kotlin/kotlin-stdlib-jdk7/1.2.21/88bfff5aa470143a83b0bc5ec00c0be8cabd7cad/kotlin-stdlib-jdk7-1.2.21.jar (version 1.2)
  /Applications/Android Studio.app/Contents/gradle/m2repository/org/jetbrains/kotlin/kotlin-stdlib-jre7/1.1.51/kotlin-stdlib-jre7-1.1.51.jar (version 1.1)
  /Users/sddsfsd/.gradle/caches/modules-2/files-2.1/org.jetbrains.kotlin/kotlin-stdlib/1.2.21/d64187eb2d9d1521be3421aa8c6774a8625cdde8/kotlin-stdlib-1.2.21.jar (version 1.2)
  </code></pre>
  
  <p>Why does Android Studio have its own older version of Kotlin in the classpath? How do I remove it?</p>