diff --git a/src/UE17_130325_Streams4/TH_Streams 2.pdf b/src/UE17_130325_Streams4/TH_Streams 2.pdf
new file mode 100644
index 0000000..0da8e61
Binary files /dev/null and b/src/UE17_130325_Streams4/TH_Streams 2.pdf differ
diff --git a/src/UE17_130325_Streams4/UE17_Streams4.java b/src/UE17_130325_Streams4/UE17_Streams4.java
index 9e43ccc..300359d 100644
--- a/src/UE17_130325_Streams4/UE17_Streams4.java
+++ b/src/UE17_130325_Streams4/UE17_Streams4.java
@@ -1,7 +1,98 @@
 package UE17_130325_Streams4;
 
-public class UE17_Streams4 {
-    public static void main(String[] args) {
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.attribute.BasicFileAttributes;
+import java.nio.file.attribute.FileTime;
+import java.util.Arrays;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
 
+public class UE17_Streams4 {
+    static Map<Character, String> letterMorseMap = Map.ofEntries(Map.entry('a', ".-"), Map.entry('b', "-..."), Map.entry('c', "-.-."), Map.entry('d', "-.."), Map.entry('e', "."), Map.entry('f', "..-."), Map.entry('g', "--."), Map.entry('h', "...."), Map.entry('i', ".."), Map.entry('j', ".---"), Map.entry('k', "-.-"), Map.entry('l', ".-.."), Map.entry('m', "--"), Map.entry('n', "-."), Map.entry('o', "---"), Map.entry('p', ".--."), Map.entry('q', "--.-"), Map.entry('r', ".-."), Map.entry('s', "..."), Map.entry('t', "-"), Map.entry('u', "..-"), Map.entry('v', "...-"), Map.entry('w', ".--"), Map.entry('x', "-..-"), Map.entry('y', "-.--"), Map.entry('z', "--.."), Map.entry('0', "-----"), Map.entry('1', ".----"), Map.entry('2', "..---"), Map.entry('3', "...--"), Map.entry('4', "....-"), Map.entry('5', "....."), Map.entry('6', "-...."), Map.entry('7', "--..."), Map.entry('8', "---.."), Map.entry('9', "----."), Map.entry('ä', ".-.-"), Map.entry('ü', "..--"), Map.entry('ö', "---."));
+    static Map<String, Character> morseLetterMap = letterMorseMap.entrySet().stream().collect(Collectors.toMap(Map.Entry::getValue, Map.Entry::getKey));
+
+    public static void main(String[] args) {
+        AtomicInteger counter = new AtomicInteger();
+        Path path = Path.of("C:/Users/alex/Downloads");
+        biggestFilesA(path, 30).forEach(p -> System.out.println(counter.getAndIncrement() + ": " + p + " - " + p.toFile().length() + " Bytes"));
+        counter.set(0);
+        System.out.println("\n");
+        biggestFilesB(path, 30).forEach(p -> System.out.println(counter.getAndIncrement() + ": " + p + " - " + p.toFile().length() + " Bytes"));
+        counter.set(0);
+        System.out.println("\n");
+        olderThan(path, Path.of("C:/Users/alex/Downloads/XG_T.docx")).forEach(p -> {
+            try {
+                System.out.println(counter.getAndIncrement() + ": " + p + " - " + Files.readAttributes(p, BasicFileAttributes.class).creationTime());
+            } catch (IOException e) {
+                throw new RuntimeException(e);
+            }
+        });
+        counter.set(0);
+        System.out.println("\n");
+        olderThan(path, Path.of("C:/Users/alex/Downloads/new")).forEach(p -> {
+            try {
+                System.out.println(counter.getAndIncrement() + ": " + p + " - " + Files.readAttributes(p, BasicFileAttributes.class).creationTime());
+            } catch (IOException e) {
+                throw new RuntimeException(e);
+            }
+        });
+        System.out.println(toMorseCode("Älle lieben Java!"));
+        System.out.println(morseToText(toMorseCode("Älle lieben Java!")));
+        System.out.println(morseToText(toMorseCode("Älle lieben Java! Älle lieben Java2")));
+    }
+
+    public static List<Path> biggestFilesA(Path dir, int n) {
+        try (Stream<Path> content = Files.walk(dir, 1)) {
+            return content.filter(Files::isRegularFile).sorted((x, y) -> Long.compare(y.toFile().length(), x.toFile().length())).limit(n).toList();
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    public static List<Path> biggestFilesB(Path dir, int n) {
+        try (Stream<Path> content = Files.walk(dir)) {
+            return content.filter(Files::isRegularFile).sorted((x, y) -> Long.compare(y.toFile().length(), x.toFile().length())).limit(n).toList();
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    public static List<Path> olderThan(Path dir, Path reference) {
+        try (Stream<Path> content = Files.list(dir)) {
+            FileTime referenceTime = Files.readAttributes(reference, BasicFileAttributes.class).creationTime();
+            return content.filter(path -> {
+                try {
+                    FileTime pathTime = Files.readAttributes(path, BasicFileAttributes.class).creationTime();
+                    if (Files.isDirectory(reference) && Files.isDirectory(path)) {
+                        return referenceTime.compareTo(pathTime) > 0;
+                    } else if (Files.isRegularFile(reference) && Files.isRegularFile(path)) {
+                        return referenceTime.compareTo(pathTime) > 0;
+                    }
+                } catch (IOException e) {
+                    return false;
+                }
+                return false;
+            }).toList();
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    public static String toMorseCode(String text) {
+        return text.toLowerCase().chars().mapToObj(c -> {
+            if (c == ' ') return "/";
+            if (String.valueOf((char) c).matches("[!.?\n]")) return "///";
+            return "/" + letterMorseMap.getOrDefault((char) c, "");
+        }).collect(Collectors.joining());
+    }
+
+
+    public static String morseToText(String morse) {
+        return Arrays.stream(morse.split("///")).map(sentence -> Arrays.stream(sentence.split("//")).map(word -> Arrays.stream(word.split("/")).map(letter -> String.valueOf(morseLetterMap.getOrDefault(letter, ' '))).collect(Collectors.joining())).collect(Collectors.joining(" ")).trim()).collect(Collectors.joining(". ")).trim();
     }
 }