HistogramDiff.scala

import scala.collection.mutable
import scala.collection.JavaConverters._

import org.eclipse.jgit.diff.{HistogramDiff, Sequence, SequenceComparator}

val histogramDiff = new HistogramDiff()
histogramDiff.setFallbackAlgorithm(null)

val deltas = histogramDiff.diff(
  new DataListComparator[Char],
  new DataList(input.toBuffer),
  new DataList(output.toBuffer)
).asScala

// ...

class DataListComparator[T] extends SequenceComparator[DataList[T]] {
  override def equals(original: DataList[T],
                      orgIdx: Int,
                      revised: DataList[T],
                      revIdx: Int): Boolean =
    original.data(orgIdx).equals(revised.data(revIdx))

  override def hash(s: DataList[T], i: Int): Int = s.data(i).hashCode()
}

class DataList[T](val data: mutable.Buffer[T]) extends Sequence {
  def size(): Int = data.length
}