scalap and javap showing different method signature

I am facing very weird issue, i am having a maven dependency in my project

<dependency>
  <groupId>org.apache.spark</groupId>
  <artifactId>spark-core_2.11</artifactId>
  <version>2.0.0</version>
</dependency>

And this is the class org.apache.spark.ui.WebUI which i am using from this dependency, and it has one method with below signature

def getHandlers : scala.Seq[org.eclipse.jetty.servlet.ServletContextHandler] = { /* compiled code */ }

but when i am executing my program, its failing with exception NoSuchMethodError.

So i started little digging it. when i decompile my jar with scalap its shows me above signature, but when i decompile with javap option, it shows different.

public scala.collection.Seq<org.spark_project.jetty.servlet.ServletContextHandler> getHandlers();