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diff --git a/‎src/main/java/streams/SimpleStream.java‎
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+package streams;
+
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.stream.IntStream;
+import java.util.stream.Stream;
+
+public class SimpleStream {
+  public static void main(String[] args) {
+    List<String> ls = List.of("Fred", "Jim", "Sheila");
+    Stream<String> ss = ls.stream();
+    ss
+        .filter(s -> s.length() > 3)
+        .forEach(s -> System.out.println(s));
+    ls.stream()
+        .forEach(s -> System.out.println(s));
+
+//    Stream.iterate(1, x -> x + 1)
+//        .forEach(x -> System.out.println(x));
+
+//    var result = Stream.iterate(1, x -> x + 1)
+//        .limit(10)
+//        .reduce(0, (a, b) -> a + b);
+//        .forEach(x -> System.out.println(x));
+
+    var result = IntStream.iterate(1, x -> x + 1)
+        .limit(0)
+        .reduce((a, b) -> a + b);
+//    System.out.println("sum is " + result);
+    result.ifPresentOrElse(x -> System.out.println("the sum is " + x),
+        () -> System.out.println("There wasn't any data"));
+
+    Map<String, String> names = Map.of("Fred", "Jones");
+    String first = "Freddy"; // assume a computation
+
+//    String last = names.get(first);
+//    String message = "Dear " + last.toUpperCase();
+//    System.out.println(message);
+
+    Optional.of(names)
+        .map(m -> m.get(first))
+        .map(l -> "Dear " + l.toUpperCase())
+        .ifPresentOrElse(x -> System.out.println(x), () -> System.out.println("No such client"));
+  }
+}