Fix issue #1044

Author: zsxwing

language-adaptors/rxjava-scala/src/examples/scala/rx/lang/scala/examples/RxScalaDemo.scala

@@ -609,4 +609,14 @@ class RxScalaDemo extends JUnitSuite {
     val m = o.toMap(keySelector, valueSelector, mapFactory)
     println(m.toBlockingObservable.single)
   }
+
+  @Test def retryExample1(): Unit = {
+    val o : Observable[String] = List("alice", "bob", "carol").toObservable
+    assertEquals(List("alice", "bob", "carol"), o.retry.toBlockingObservable.toList)
+  }
+
+  @Test def retryExample2(): Unit = {
+    val o : Observable[String] = List("alice", "bob", "carol").toObservable
+    assertEquals(List("alice", "bob", "carol"), o.retry(3).toBlockingObservable.toList)
+  }
 }

language-adaptors/rxjava-scala/src/main/scala/rx/lang/scala/Observable.scala

@@ -2115,7 +2115,7 @@ trait Observable[+T]
    * emits [1, 2, 3, 4, 5] then the complete output would be [1, 2, 1, 2, 3, 4, 5, onCompleted].
    * @return Observable with retry logic.
    */
-  def retry: Observable[T] = {
+  def retry(): Observable[T] = {
     toScalaObservable[T](asJavaObservable.retry())
   }