how to calculate the cosine similarity between two files?

I am using spark and scala to implement an issue. files contain phrases or sentences. I want to use domain based method to calculate the cosine similarity between tags.I convert two files into a string and then calculate the similarity.

code

  val lines=Source.fromURL(Source.getClass().getResource(file:///usr/loca/spark/dataset/algorithm3/comedy)).mkString(\n)

      val lines2=Source.fromURL(Source.getClass().getResource(file:///usr/local/spark/dataset/algorithm3/funny)).mkString(\n)

   val result=textCosine(lines,lines2)
   println(The cosine similarity score: +result)
  }
 
  def module(vec:Vector[Double]): Double ={
    math.sqrt(vec.map(math.pow(_,2)).sum)
  }

  def innerProduct(v1:Vector[Double],v2:Vector[Double]): Double ={
    val listBuffer=ListBuffer[Double]()
    for(i- 0 until v1.length; j- 0 until v2.length;if i==j){
      if(i==j){
        listBuffer.append( v1(i)*v2(j) )
      }
    }
    listBuffer.sum
  }

  def cosvec(v1:Vector[Double],v2:Vector[Double]):Double ={
    val cos=innerProduct(v1,v2) / (module(v1)* module(v2))
    if (cos = 1) cos else 1.0
  }
 
  def textCosine(lines:String,lines2:String):Double={
         val set=mutable.Set[Char]() 
    lines.foreach(set +=_)
    lines2.foreach(set +=_)
    println(set)
    val ints1: Vector[Double] = set.toList.sorted.map(ch = {
      lines.count(s = s == ch).toDouble
    }).toVector
    println(===ints1: +ints1)
    val ints2: Vector[Double] = set.toList.sorted.map(ch = {
      lines2.count(s = s == ch).toDouble
    }).toVector
    println(===ints2: +ints2)
    cosvec(ints1,ints2)
  }
  
}

but the output gives me error:

 Exception in thread main java.lang.NullPointerException
    at scala.io.Source$.fromURL(Source.scala:141)
    at com.algorithm.similarity$.main(similarity.scala:18)
    at com.algorithm.similarity.main(similarity.scala)

How to solve it?