diff --git a/src/org/eidecker/oca8lernen/general/PredicateTest.java b/src/org/eidecker/oca8lernen/general/PredicateTest.java
new file mode 100644
index 0000000..650de2f
--- /dev/null
+++ b/src/org/eidecker/oca8lernen/general/PredicateTest.java
@@ -0,0 +1,39 @@
+package org.eidecker.oca8lernen.general;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.util.function.Predicate;
+import org.junit.jupiter.api.Test;
+
+public class PredicateTest {
+
+	Predicate<String> isEmpty = (String s) -> s.length() == 0;
+
+	Predicate<String> isNotEmpty = s -> {return true;};
+
+	Predicate<String> isEmptyKomisch = new IsEmpty();
+
+	@Test
+	public void testPredicates() {
+		assertFalse(applyPredicate("Hallo", isEmpty));
+
+		assertTrue(applyPredicate("", isEmpty));
+
+		assertTrue(applyPredicate("", isEmptyKomisch));
+	}
+
+	private boolean applyPredicate(String s, Predicate<String> tester) {
+		return tester.test(s);
+	}
+
+
+}
+
+class IsEmpty implements Predicate<String> {
+
+	@Override
+	public boolean test(String s) {
+		return s.length() == 0;
+	}
+}
diff --git a/src/org/eidecker/oca8lernen/general/PrimitiveUndWrapperTest.java b/src/org/eidecker/oca8lernen/general/PrimitiveUndWrapperTest.java
index e5df14c..f43c01d 100644
--- a/src/org/eidecker/oca8lernen/general/PrimitiveUndWrapperTest.java
+++ b/src/org/eidecker/oca8lernen/general/PrimitiveUndWrapperTest.java
@@ -68,8 +68,8 @@ public class PrimitiveUndWrapperTest {
 		System.out.println("double");
 	}
 
-	public static void  main(String... args) {
-		new PrimitiveUndWrapperTest().stringConcat();
+	public static void  main(String... args) throws Exception {
+		new PrimitiveUndWrapperTest().stringConcat(); // Auch main muss Exceptions deklarieren
 	}
 
 
@@ -93,8 +93,7 @@ class Ober {
 class Unter extends Ober {
 	@Override
 	HeaderList getList() {
-		new Character()
-		super.getList().size()
+		super.getList().size();
 		return null;
 	}
 }
\ No newline at end of file