diff --git a/Kitodo-API/src/main/java/org/kitodo/serviceloader/KitodoServiceLoader.java b/Kitodo-API/src/main/java/org/kitodo/serviceloader/KitodoServiceLoader.java
index 993c9a0ec63..9e99e64bc9e 100644
--- a/Kitodo-API/src/main/java/org/kitodo/serviceloader/KitodoServiceLoader.java
+++ b/Kitodo-API/src/main/java/org/kitodo/serviceloader/KitodoServiceLoader.java
@@ -20,7 +20,6 @@
 import java.net.URL;
 import java.net.URLClassLoader;
 import java.nio.file.DirectoryStream;
-import java.nio.file.FileSystems;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
@@ -80,8 +79,7 @@ public class KitodoServiceLoader<T> {
     private static final String JAR = "*.jar";
     private static final String ERROR = "Classpath could not be accessed";
 
-    private static final Path SYSTEM_TEMP_FOLDER = FileSystems.getDefault()
-            .getPath(System.getProperty("java.io.tmpdir"));
+    private static final Path SYSTEM_TEMP_FOLDER = Paths.get(System.getProperty("java.io.tmpdir"));
 
     private static final Logger logger = LogManager.getLogger(KitodoServiceLoader.class);
 
@@ -142,7 +140,7 @@ public List<T> loadModules() {
      * they can be used in all frontend files
      */
     private void loadBeans() {
-        Path moduleFolder = FileSystems.getDefault().getPath(modulePath);
+        Path moduleFolder = Paths.get(modulePath);
         try (DirectoryStream<Path> stream = Files.newDirectoryStream(moduleFolder, JAR)) {
             for (Path f : stream) {
                 try (JarFile jarFile = new JarFile(f.toString())) {
@@ -197,7 +195,7 @@ private void loadBeans() {
      */
     private void loadFrontendFilesIntoCore() {
 
-        Path moduleFolder = FileSystems.getDefault().getPath(modulePath);
+        Path moduleFolder = Paths.get(modulePath);
 
         try (DirectoryStream<Path> stream = Files.newDirectoryStream(moduleFolder, JAR)) {
 
@@ -382,7 +380,7 @@ private File findFile(String name, File folder) throws FileNotFoundException {
      * earlier class loader created at an earlier time.</p>
      */
     private void loadModulesIntoClasspath() {
-        Path moduleFolder = FileSystems.getDefault().getPath(modulePath);
+        Path moduleFolder = Paths.get(modulePath);
 
         try (DirectoryStream<Path> stream = Files.newDirectoryStream(moduleFolder, JAR)) {
 
diff --git a/Kitodo-API/src/test/java/org/kitodo/config/KitodoConfigTest.java b/Kitodo-API/src/test/java/org/kitodo/config/KitodoConfigTest.java
index 6ef8f926401..947f49b2493 100644
--- a/Kitodo-API/src/test/java/org/kitodo/config/KitodoConfigTest.java
+++ b/Kitodo-API/src/test/java/org/kitodo/config/KitodoConfigTest.java
@@ -22,13 +22,16 @@
 
 import java.util.NoSuchElementException;
 
+import org.junit.jupiter.api.AfterAll;
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.Test;
 import org.kitodo.config.enums.ParameterAPI;
+import org.mockito.MockedStatic;
 
 public class KitodoConfigTest {
 
     private static ParameterAPI NONE;
+    private static MockedStatic<ParameterAPI> mockedParameterAPI;
 
     /**
      * Init once before tests.
@@ -40,12 +43,17 @@ public static void init() {
         NONE = mock(ParameterAPI.class);
         doReturn(3).when(NONE).ordinal();
 
-        mockStatic(ParameterAPI.class);
+        mockedParameterAPI = mockStatic(ParameterAPI.class);
         when(ParameterAPI.values())
                 .thenReturn(new ParameterAPI[] {ParameterAPI.DIR_MODULES, ParameterAPI.DIR_PROCESSES,
                                                 ParameterAPI.DIR_XML_CONFIG, NONE });
     }
 
+    @AfterAll
+    public static void tearDown() {
+        mockedParameterAPI.close();
+    }
+
     @Test
     public void shouldGetStringParameterWithoutDefault() {
         String param = KitodoConfig.getParameter(ParameterAPI.DIR_XML_CONFIG);
diff --git a/Kitodo-DataEditor/src/test/java/org/kitodo/dataeditor/DataEditorTest.java b/Kitodo-DataEditor/src/test/java/org/kitodo/dataeditor/DataEditorTest.java
index 56937bfb6ad..777a1736127 100644
--- a/Kitodo-DataEditor/src/test/java/org/kitodo/dataeditor/DataEditorTest.java
+++ b/Kitodo-DataEditor/src/test/java/org/kitodo/dataeditor/DataEditorTest.java
@@ -16,6 +16,7 @@
 
 import java.io.File;
 import java.io.IOException;
+import java.io.OutputStream;
 import java.net.URI;
 import java.nio.file.Files;
 import java.nio.file.Paths;
@@ -43,8 +44,12 @@ public void saveFile() throws IOException {
 
     @AfterEach
     public void revertFile() throws IOException {
-        IOUtils.write( testMetaOldFormat, Files.newOutputStream(Paths.get(pathOfOldMetaFormat)));
-        IOUtils.write( testmetaUnsupportedFormat, Files.newOutputStream(Paths.get("src/test/resources/testmetaUnsupportedFormat.xml")));
+        try (OutputStream out1 = Files.newOutputStream(Paths.get(pathOfOldMetaFormat))) {
+            IOUtils.write(testMetaOldFormat, out1);
+        }
+        try (OutputStream out2 = Files.newOutputStream(Paths.get("src/test/resources/testmetaUnsupportedFormat.xml"))) {
+            IOUtils.write(testmetaUnsupportedFormat, out2);
+        }
     }
 
     @Test
diff --git a/Kitodo-DataEditor/src/test/java/org/kitodo/dataeditor/MetsKitodoConverterTest.java b/Kitodo-DataEditor/src/test/java/org/kitodo/dataeditor/MetsKitodoConverterTest.java
index d2353047787..88d9ff0aa34 100644
--- a/Kitodo-DataEditor/src/test/java/org/kitodo/dataeditor/MetsKitodoConverterTest.java
+++ b/Kitodo-DataEditor/src/test/java/org/kitodo/dataeditor/MetsKitodoConverterTest.java
@@ -15,6 +15,7 @@
 
 import java.io.File;
 import java.io.IOException;
+import java.io.OutputStream;
 import java.net.URI;
 import java.nio.file.Files;
 import java.nio.file.Paths;
@@ -46,7 +47,9 @@ public void saveFile() throws IOException {
 
     @AfterEach
     public void revertFile() throws IOException {
-        IOUtils.write( testMetaOldFormat, Files.newOutputStream(Paths.get(pathOfOldMetaFormat)));
+        try (OutputStream out = Files.newOutputStream(Paths.get(pathOfOldMetaFormat))) {
+            IOUtils.write(testMetaOldFormat, out);
+        }
     }
 
     @Test
diff --git a/Kitodo-DataEditor/src/test/java/org/kitodo/dataeditor/MetsKitodoValidatorTest.java b/Kitodo-DataEditor/src/test/java/org/kitodo/dataeditor/MetsKitodoValidatorTest.java
index 2e27f84806e..537cf775263 100644
--- a/Kitodo-DataEditor/src/test/java/org/kitodo/dataeditor/MetsKitodoValidatorTest.java
+++ b/Kitodo-DataEditor/src/test/java/org/kitodo/dataeditor/MetsKitodoValidatorTest.java
@@ -16,6 +16,7 @@
 
 import java.io.File;
 import java.io.IOException;
+import java.io.OutputStream;
 import java.nio.file.Files;
 import java.nio.file.Paths;
 
@@ -39,7 +40,9 @@ public void saveFile() throws IOException {
 
     @AfterEach
     public void revertFile() throws IOException {
-        IOUtils.write( testMetaOldFormat, Files.newOutputStream(Paths.get(pathOfOldMetaFormat)));
+        try (OutputStream out = Files.newOutputStream(Paths.get(pathOfOldMetaFormat))) {
+            IOUtils.write(testMetaOldFormat, out);
+        }
     }
 
     @Test
diff --git a/Kitodo-DataEditor/src/test/java/org/kitodo/dataeditor/MetsKitodoWrapperTest.java b/Kitodo-DataEditor/src/test/java/org/kitodo/dataeditor/MetsKitodoWrapperTest.java
index ef74623d6e0..bcc93021e41 100644
--- a/Kitodo-DataEditor/src/test/java/org/kitodo/dataeditor/MetsKitodoWrapperTest.java
+++ b/Kitodo-DataEditor/src/test/java/org/kitodo/dataeditor/MetsKitodoWrapperTest.java
@@ -17,6 +17,7 @@
 
 import java.io.File;
 import java.io.IOException;
+import java.io.OutputStream;
 import java.math.BigInteger;
 import java.net.URI;
 import java.nio.file.Files;
@@ -65,7 +66,9 @@ public void saveFile() throws IOException {
 
     @AfterEach
     public void revertFile() throws IOException {
-        IOUtils.write( testMetaOldFormat, Files.newOutputStream(Paths.get(pathOfOldMetaFormat)));
+        try (OutputStream out = Files.newOutputStream(Paths.get(pathOfOldMetaFormat))) {
+            IOUtils.write(testMetaOldFormat, out);
+        }
     }
 
     @BeforeAll
diff --git a/Kitodo-DataEditor/src/test/java/org/kitodo/dataeditor/MetsKitodoWriterTest.java b/Kitodo-DataEditor/src/test/java/org/kitodo/dataeditor/MetsKitodoWriterTest.java
index 0afe470acfa..c0517c16823 100644
--- a/Kitodo-DataEditor/src/test/java/org/kitodo/dataeditor/MetsKitodoWriterTest.java
+++ b/Kitodo-DataEditor/src/test/java/org/kitodo/dataeditor/MetsKitodoWriterTest.java
@@ -16,6 +16,7 @@
 
 import java.io.File;
 import java.io.IOException;
+import java.io.OutputStream;
 import java.net.URI;
 import java.nio.file.Files;
 import java.nio.file.Paths;
@@ -49,7 +50,9 @@ public void saveFile() throws IOException {
 
     @AfterEach
     public void revertFile() throws IOException {
-        IOUtils.write( testMetaOldFormat, Files.newOutputStream(Paths.get(pathOfOldMetaFormat)));
+        try (OutputStream out = Files.newOutputStream(Paths.get(pathOfOldMetaFormat))) {
+            IOUtils.write(testMetaOldFormat, out);
+        }
     }
 
     @BeforeAll
diff --git a/Kitodo-DataFormat/src/test/java/org/kitodo/dataformat/access/MetsXmlElementAccessIT.java b/Kitodo-DataFormat/src/test/java/org/kitodo/dataformat/access/MetsXmlElementAccessIT.java
index d0662885378..2332451bd4d 100644
--- a/Kitodo-DataFormat/src/test/java/org/kitodo/dataformat/access/MetsXmlElementAccessIT.java
+++ b/Kitodo-DataFormat/src/test/java/org/kitodo/dataformat/access/MetsXmlElementAccessIT.java
@@ -297,18 +297,19 @@ public void duplicateMetsFileDefinitionWithoutStrictFileIdCheck() throws IOExcep
     public void duplicateMetsFileDefinitionWithStrictFileIdCheck() {
         // mock access to KitodoConfig usage
         PropertiesConfiguration propertiesConfiguration = Mockito.mock(PropertiesConfiguration.class);
-        MockedStatic<KitodoConfig> mockedConfig = Mockito.mockStatic(KitodoConfig.class);
-        mockedConfig.when(KitodoConfig::getConfig).thenReturn(propertiesConfiguration);
-        // mock getBoolean method call like in the main class
-        Mockito.when(propertiesConfiguration.getBoolean("useStrictMetsFileIdCheck", false)).thenReturn(true);
-
-        Exception exception = assertThrows(IllegalArgumentException.class,
-                () -> new MetsXmlElementAccess().read(
-                        new FileInputStream("src/test/resources/meta_duplicate_file.xml")
-                )
-            );
-
-        assertEquals("Corrupt file: each METS file ID has to be unique but FILE_0001 is used multiple times!", exception.getMessage());
+        try (MockedStatic<KitodoConfig> mockedConfig = Mockito.mockStatic(KitodoConfig.class)) {
+            mockedConfig.when(KitodoConfig::getConfig).thenReturn(propertiesConfiguration);
+            // mock getBoolean method call like in the main class
+            Mockito.when(propertiesConfiguration.getBoolean("useStrictMetsFileIdCheck", false)).thenReturn(true);
+
+            Exception exception = assertThrows(IllegalArgumentException.class,
+                    () -> new MetsXmlElementAccess().read(
+                            new FileInputStream("src/test/resources/meta_duplicate_file.xml")
+                    )
+                );
+
+            assertEquals("Corrupt file: each METS file ID has to be unique but FILE_0001 is used multiple times!", exception.getMessage());
+        }
     }
 
     @Test
diff --git a/Kitodo/src/main/java/org/kitodo/production/services/file/FileService.java b/Kitodo/src/main/java/org/kitodo/production/services/file/FileService.java
index 08e92325042..172cb22058f 100644
--- a/Kitodo/src/main/java/org/kitodo/production/services/file/FileService.java
+++ b/Kitodo/src/main/java/org/kitodo/production/services/file/FileService.java
@@ -141,8 +141,7 @@ URI createMetaDirectory(URI parentFolderUri, String directoryName) throws IOExce
             logger.info("Metadata directory: {} already existed! No new directory was created", directoryName);
         } else {
             CommandService commandService = ServiceManager.getCommandService();
-            String path = FileSystems.getDefault()
-                    .getPath(ConfigCore.getKitodoDataDirectory(), parentFolderUri.getRawPath(), directoryName)
+            String path = Paths.get(ConfigCore.getKitodoDataDirectory(), parentFolderUri.getRawPath(), directoryName)
                     .normalize().toAbsolutePath().toString();
             List<String> commandParameter = Collections.singletonList(path);
             File script = new File(ConfigCore.getParameter(ParameterCore.SCRIPT_CREATE_DIR_META));
diff --git a/Kitodo/src/test/java/org/kitodo/production/forms/dataeditor/MediaPartialFormTest.java b/Kitodo/src/test/java/org/kitodo/production/forms/dataeditor/MediaPartialFormTest.java
index 36c3c18fab6..567953f5e35 100644
--- a/Kitodo/src/test/java/org/kitodo/production/forms/dataeditor/MediaPartialFormTest.java
+++ b/Kitodo/src/test/java/org/kitodo/production/forms/dataeditor/MediaPartialFormTest.java
@@ -23,6 +23,7 @@
 import java.util.LinkedList;
 
 import org.apache.commons.lang3.tuple.ImmutablePair;
+import org.junit.jupiter.api.AfterAll;
 import org.junit.jupiter.api.BeforeAll;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
@@ -48,6 +49,7 @@ public class MediaPartialFormTest {
     PhysicalDivision physicalDivision;
     PhysicalDivision physicalStructure;
 
+    private static MockedStatic<Ajax> ajaxMockedStatic;
 
     /**
      * Initialize test class.
@@ -55,12 +57,22 @@ public class MediaPartialFormTest {
     @BeforeAll
     public static void initTestClass() {
         // mock frontend update calls
-        Mockito.mockStatic(Ajax.class);
+        ajaxMockedStatic = Mockito.mockStatic(Ajax.class);
         PrimeFaces primeFaces = mock(PrimeFaces.class);
         MockedStatic<PrimeFaces> primefacesSingleton = Mockito.mockStatic(PrimeFaces.class);
         primefacesSingleton.when(PrimeFaces::current).thenReturn(primeFaces);
     }
 
+    /**
+     * Clean up static mocks.
+     */
+    @AfterAll
+    public static void cleanupTestClass() {
+        if (ajaxMockedStatic != null) {
+            ajaxMockedStatic.close();
+        }
+    }
+
     /**
      * Initialize test function.
      */
diff --git a/Kitodo/src/test/java/org/kitodo/production/services/dataeditor/DataEditorServiceTest.java b/Kitodo/src/test/java/org/kitodo/production/services/dataeditor/DataEditorServiceTest.java
index 03aaab15c06..184a62d3efe 100644
--- a/Kitodo/src/test/java/org/kitodo/production/services/dataeditor/DataEditorServiceTest.java
+++ b/Kitodo/src/test/java/org/kitodo/production/services/dataeditor/DataEditorServiceTest.java
@@ -17,6 +17,7 @@
 
 import java.io.File;
 import java.io.IOException;
+import java.io.OutputStream;
 import java.nio.file.Files;
 import java.nio.file.Paths;
 
@@ -45,7 +46,9 @@ public void saveFile() throws IOException {
 
     @AfterEach
     public void revertFile() throws IOException {
-        IOUtils.write( testMetaOldFormat, Files.newOutputStream(Paths.get(pathOfOldMetaFormat)));
+        try (OutputStream out = Files.newOutputStream(Paths.get(pathOfOldMetaFormat))) {
+            IOUtils.write(testMetaOldFormat, out);
+        }
     }
 
     @Test