update

.idea/misc.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_10" project-jdk-name="10" project-jdk-type="JavaSDK">
+    <output url="file://$PROJECT_DIR$/out" />
+  </component>
+</project>

.idea/modules.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ProjectModuleManager">
+    <modules>
+      <module fileurl="file://$PROJECT_DIR$/ChareSWE.iml" filepath="$PROJECT_DIR$/ChareSWE.iml" />
+    </modules>
+  </component>
+</project>

ChareSWE.iml

+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
+    </content>
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+  </component>
+</module>

src/HelloWorld.java

-public class HelloWorld {
-    public static void main(String[] args) {
-
-        System.out.println("Hallo Welt");
-    }
-}

src/TestGumbert.java

-import org.junit.Test;
-import static org.junit.Assert.*;
-
-
-@Test
-public class TestGumbert {
-
-}