title: Class is not abstract and does not implement abstract base class member
body: <p>I'm confused by this Kotlin error associated with providing an implementation for an abstract class that has been imported from a maven package.</p>
  
  <p>I have a maven library that is written in Kotlin and exposes an abstract class called APIGatewayRequestHandler.  In my app that imports the library, I provide an implementation of the abstract class:</p>
  
  <pre><code>class GetWelcomeMessageHandler : APIGatewayRequestHandler&lt;WelcomeMessage&gt;()
      fun handleAPIGatewayRequest(input: com.amazonaws.services.lambda.runtime.events.APIGatewayProxyRequestEvent, context: com.amazonaws.services.lambda.runtime.Context?): WelcomeMessage {
          return WelcomeMessage()
      }
  }
  </code></pre>
  
  <p>The decompiled abstract class from the library looks like this:</p>
  
  <pre><code>public abstract class APIGatewayRequestHandler&lt;T&gt; public constructor() : com.amazonaws.services.lambda.runtime.RequestHandler&lt;com.amazonaws.services.lambda.runtime.events.APIGatewayProxyRequestEvent, T&gt; {
      public abstract fun handleAPIGatewayRequest(input: com.amazonaws.services.lambda.runtime.events.APIGatewayProxyRequestEvent, context: com.amazonaws.services.lambda.runtime.Context?): T
  
      public open fun handleRequest(input: com.amazonaws.services.lambda.runtime.events.APIGatewayProxyRequestEvent?, context: com.amazonaws.services.lambda.runtime.Context?): T {
          /* compiled code */
      }
  }
  </code></pre>
  
  <p>I get the following error:</p>
  
  <pre><code>Class 'GetWelcomeMessageHandler' is not abstract and does not implement abstract base class member
  public abstract fun handleAPIGatewayRequest(input: APIGatewayProxyRequestEvent, context: Context?): WelcomeMessage
  </code></pre>