Added assert instead of IAE

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

@@ -475,35 +475,32 @@ abstract class RDD[T: ClassTag](
       seed: Long = Utils.random.nextLong): Array[T] = withScope {
     val numStDev = 10.0
 
-    if (num < 0) {
-      throw new IllegalArgumentException("Negative number of elements requested")
-    } else if (num > (Int.MaxValue - (numStDev * math.sqrt(Int.MaxValue)).toInt)) {
-      throw new IllegalArgumentException("Cannot support a sample size > Int.MaxValue - " +
-      s"$numStDev * math.sqrt(Int.MaxValue)")
+    require(num > 0, "Negative number of elements requested")
+    require(num <= (Int.MaxValue - (numStDev * math.sqrt(Int.MaxValue)).toInt),
+      "Cannot support a sample size > Int.MaxValue - " +
+        s"$numStDev * math.sqrt(Int.MaxValue)")
+
+    val initialCount = this.count()
+    if (num == 0 || initialCount == 0 ) {
+      new Array[T](0)
     } else {
-      val initialCount = this.count()
-      if (num == 0 || initialCount == 0 ) {
-        new Array[T](0)
+      val rand = new Random(seed)
+      if (!withReplacement && num >= initialCount) {
+        Utils.randomizeInPlace(this.collect(), rand)
       } else {
-        val rand = new Random(seed)
-        if (!withReplacement && num >= initialCount) {
-          Utils.randomizeInPlace(this.collect(), rand)
-        } else {
-          val fraction = SamplingUtils.computeFractionForSampleSize(num, initialCount,
-            withReplacement)
-
-          var samples = this.sample(withReplacement, fraction, rand.nextInt()).collect()
-
-          // If the first sample didn't turn out large enough, keep trying to take samples;
-          // this shouldn't happen often because we use a big multiplier for the initial size
-          var numIters = 0
-          while (samples.length < num) {
-            logWarning(s"Needed to re-sample due to insufficient sample size. Repeat #$numIters")
-            samples = this.sample(withReplacement, fraction, rand.nextInt()).collect()
-            numIters += 1
-          }
-          Utils.randomizeInPlace(samples, rand).take(num)
+        val fraction = SamplingUtils.computeFractionForSampleSize(num, initialCount,
+          withReplacement)
+        var samples = this.sample(withReplacement, fraction, rand.nextInt()).collect()
+
+        // If the first sample didn't turn out large enough, keep trying to take samples;
+        // this shouldn't happen often because we use a big multiplier for the initial size
+        var numIters = 0
+        while (samples.length < num) {
+          logWarning(s"Needed to re-sample due to insufficient sample size. Repeat #$numIters")
+          samples = this.sample(withReplacement, fraction, rand.nextInt()).collect()
+          numIters += 1
         }
+        Utils.randomizeInPlace(samples, rand).take(num)
       }
     }
   }