diff --git a/biopet-tools/src/main/scala/nl/lumc/sasc/biopet/tools/bamstats/BamStats.scala b/biopet-tools/src/main/scala/nl/lumc/sasc/biopet/tools/bamstats/BamStats.scala
index bf8acd07e51a0ab78f9d0c6484c927a6933ea4ee..385a6b5ce4822be725fed45b20a4cfefdfab10d7 100644
--- a/biopet-tools/src/main/scala/nl/lumc/sasc/biopet/tools/bamstats/BamStats.scala
+++ b/biopet-tools/src/main/scala/nl/lumc/sasc/biopet/tools/bamstats/BamStats.scala
@@ -2,18 +2,15 @@ package nl.lumc.sasc.biopet.tools.bamstats
 
 import java.io.File
 
-import htsjdk.samtools.{ CigarOperator, SAMSequenceDictionary, SamReaderFactory }
 import htsjdk.samtools.reference.FastaSequenceFile
+import htsjdk.samtools.{ SAMSequenceDictionary, SamReaderFactory }
 import nl.lumc.sasc.biopet.utils.BamUtils.SamDictCheck
+import nl.lumc.sasc.biopet.utils.ToolCommand
 import nl.lumc.sasc.biopet.utils.intervals.{ BedRecord, BedRecordList }
-import nl.lumc.sasc.biopet.utils.{ BamUtils, ToolCommand }
 
-import scala.concurrent.ExecutionContext.Implicits.global
-import scala.concurrent.{ Await, Future }
-import scala.concurrent.blocking
-import scala.util.{ Failure, Success }
-import scala.concurrent.duration.Duration
 import scala.collection.JavaConversions._
+import scala.concurrent.ExecutionContext.Implicits.global
+import scala.concurrent.Future
 
 /**
  * Created by pjvanthof on 25/05/16.
diff --git a/biopet-tools/src/main/scala/nl/lumc/sasc/biopet/tools/bamstats/Histogram.scala b/biopet-tools/src/main/scala/nl/lumc/sasc/biopet/tools/bamstats/Histogram.scala
index 64be8768003449b7db21477d89f5b6f11a0c5015..6a97e23032ecb300f44fb949f1fc5b8c929e6dbc 100644
--- a/biopet-tools/src/main/scala/nl/lumc/sasc/biopet/tools/bamstats/Histogram.scala
+++ b/biopet-tools/src/main/scala/nl/lumc/sasc/biopet/tools/bamstats/Histogram.scala
@@ -2,9 +2,7 @@ package nl.lumc.sasc.biopet.tools.bamstats
 
 import java.io.{ File, PrintWriter }
 
-import scala.collection.generic.Sorted
 import scala.collection.mutable
-import scala.math.ScalaNumber
 
 /**
  * Created by pjvanthof on 05/07/16.
@@ -12,15 +10,18 @@ import scala.math.ScalaNumber
 case class Histogram() {
   protected[Histogram] val histrogram: mutable.Map[Int, Long] = mutable.Map()
 
+  /** This will add an other histogram to `this` */
   def +=(other: Histogram): Histogram = {
     other.histrogram.foreach(x => this.histrogram += x._1 -> (this.histrogram.getOrElse(x._1, 0L) + x._2))
     this
   }
 
+  /** With this a value can be added to the histogram */
   def add(value: Int): Unit = {
     histrogram += value -> (histrogram.getOrElse(value, 0L) + 1)
   }
 
+  /** Write histogram to a tsv/count file */
   def writeToTsv(file: File): Unit = {
     val writer = new PrintWriter(file)
     writer.println("value\tcount")
diff --git a/biopet-tools/src/main/scala/nl/lumc/sasc/biopet/tools/bamstats/Stats.scala b/biopet-tools/src/main/scala/nl/lumc/sasc/biopet/tools/bamstats/Stats.scala
index aa3a58963412ef376681c3a43560d5339ceca65f..cc3e72f898d3969cc1214fc680d891add5d00680 100644
--- a/biopet-tools/src/main/scala/nl/lumc/sasc/biopet/tools/bamstats/Stats.scala
+++ b/biopet-tools/src/main/scala/nl/lumc/sasc/biopet/tools/bamstats/Stats.scala
@@ -1,8 +1,5 @@
 package nl.lumc.sasc.biopet.tools.bamstats
 
-import scala.collection.mutable
-import scala.concurrent.blocking
-
 /**
  * Created by pjvanthof on 05/07/16.
  */