Spark Data frames joining with common columns

Join two data frames with the same column names as join column.
Need to generate the final column list with only one join column.
The solution is to rename the join column in the second DF before joining.

def joinTwoDFs(df1:DataFrame, df2:DataFrame, joinKey: String, joinType: String): DataFrame = {

    val colList1 = df1.columns.toList
    val colList2 = df2.columns.toList

    val targetColList = colList1.filterNot( _ == joinKey)  ++  colList2.filterNot( _ == joinKey)

    val joinKey2 = "tmp_" + joinKey

    val tmpDf2 = df2.withColumnRenamed(joinKey, joinKey2)

    val targetDf = df1.join(tmpDf2, dataset1(joinKey) === tmpDf2(joinKey2),
               joinType).select(joinKey, targetColList.toSeq : _*)

    targetDf
  }