fix other similar error message.

Author: WeichenXu123

core/src/main/scala/org/apache/spark/rdd/PairRDDFunctions.scala

@@ -83,7 +83,7 @@ class PairRDDFunctions[K, V](self: RDD[(K, V)])
         throw new SparkException("Cannot use map-side combining with array keys.")
       }
       if (partitioner.isInstanceOf[HashPartitioner]) {
-        throw new SparkException("Default partitioner cannot partition array keys.")
+        throw new SparkException("Specified or default partitioner cannot partition array keys.")
       }
     }
     val aggregator = new Aggregator[K, V, C](
@@ -784,7 +784,7 @@ class PairRDDFunctions[K, V](self: RDD[(K, V)])
       partitioner: Partitioner)
       : RDD[(K, (Iterable[V], Iterable[W1], Iterable[W2], Iterable[W3]))] = self.withScope {
     if (partitioner.isInstanceOf[HashPartitioner] && keyClass.isArray) {
-      throw new SparkException("Default partitioner cannot partition array keys.")
+      throw new SparkException("Specified or default partitioner cannot partition array keys.")
     }
     val cg = new CoGroupedRDD[K](Seq(self, other1, other2, other3), partitioner)
     cg.mapValues { case Array(vs, w1s, w2s, w3s) =>
@@ -802,7 +802,7 @@ class PairRDDFunctions[K, V](self: RDD[(K, V)])
   def cogroup[W](other: RDD[(K, W)], partitioner: Partitioner)
       : RDD[(K, (Iterable[V], Iterable[W]))] = self.withScope {
     if (partitioner.isInstanceOf[HashPartitioner] && keyClass.isArray) {
-      throw new SparkException("Default partitioner cannot partition array keys.")
+      throw new SparkException("Specified or default partitioner cannot partition array keys.")
     }
     val cg = new CoGroupedRDD[K](Seq(self, other), partitioner)
     cg.mapValues { case Array(vs, w1s) =>
@@ -817,7 +817,7 @@ class PairRDDFunctions[K, V](self: RDD[(K, V)])
   def cogroup[W1, W2](other1: RDD[(K, W1)], other2: RDD[(K, W2)], partitioner: Partitioner)
       : RDD[(K, (Iterable[V], Iterable[W1], Iterable[W2]))] = self.withScope {
     if (partitioner.isInstanceOf[HashPartitioner] && keyClass.isArray) {
-      throw new SparkException("Default partitioner cannot partition array keys.")
+      throw new SparkException("Specified or default partitioner cannot partition array keys.")
     }
     val cg = new CoGroupedRDD[K](Seq(self, other1, other2), partitioner)
     cg.mapValues { case Array(vs, w1s, w2s) =>