diff --git a/com.avaloq.tools.ddk.check.core.test/src/com/avaloq/tools/ddk/check/core/test/AbstractCheckTestCase.java b/com.avaloq.tools.ddk.check.core.test/src/com/avaloq/tools/ddk/check/core/test/AbstractCheckTestCase.java
index 21ac794f36..5f61ec19aa 100644
--- a/com.avaloq.tools.ddk.check.core.test/src/com/avaloq/tools/ddk/check/core/test/AbstractCheckTestCase.java
+++ b/com.avaloq.tools.ddk.check.core.test/src/com/avaloq/tools/ddk/check/core/test/AbstractCheckTestCase.java
@@ -183,8 +183,7 @@ protected String getFileName(final String name) {
    *           the exception
    */
   public String getContents(final IFile file) throws Exception { // NOPMD
-    InputStream inputStream = file.getContents();
-    try {
+    try (InputStream inputStream = file.getContents()) {
       byte[] buffer = new byte[TWO_KILO_BYTES];
       int bytesRead;
       StringBuffer b = new StringBuffer();
@@ -195,8 +194,6 @@ public String getContents(final IFile file) throws Exception { // NOPMD
         }
       } while (bytesRead != -1);
       return b.toString();
-    } finally {
-      inputStream.close();
     }
   }
 
@@ -251,18 +248,8 @@ public ResourceSet getResourceSet() {
   public EObject getModel(final String fileName) throws Exception { // NOPMD
     IFile file = getFile(fileName);
     Resource resource = get(XtextResourceSet.class).createResource(uri(file));
-    InputStream s = null;
-    try {
-      s = file.getContents();
+    try (InputStream s = file.getContents()) {
       resource.load(s, null);
-    } finally {
-      if (s != null) {
-        try {
-          s.close();
-        } catch (IOException e) {
-          LOGGER.info("Failed to close test file " + fileName);
-        }
-      }
     }
     assertEquals(0, resource.getErrors().size(), resource.getErrors().toString());
     return resource.getContents().get(0);
diff --git a/com.avaloq.tools.ddk.check.ui/src/com/avaloq/tools/ddk/check/ui/builder/CheckExtensionGenerator.java b/com.avaloq.tools.ddk.check.ui/src/com/avaloq/tools/ddk/check/ui/builder/CheckExtensionGenerator.java
index 88f6f5e13d..6d5f97d823 100644
--- a/com.avaloq.tools.ddk.check.ui/src/com/avaloq/tools/ddk/check/ui/builder/CheckExtensionGenerator.java
+++ b/com.avaloq.tools.ddk.check.ui/src/com/avaloq/tools/ddk/check/ui/builder/CheckExtensionGenerator.java
@@ -22,8 +22,6 @@
 import javax.xml.parsers.ParserConfigurationException;
 import javax.xml.parsers.SAXParserFactory;
 
-import org.apache.logging.log4j.LogManager;
-import org.apache.logging.log4j.Logger;
 import org.eclipse.core.resources.IFile;
 import org.eclipse.core.resources.IProject;
 import org.eclipse.core.runtime.CoreException;
@@ -91,8 +89,6 @@
 @SuppressWarnings({"restriction", "nls"})
 class CheckExtensionGenerator {
   // CHECKSTYLE:ON
-  private static final Logger LOGGER = LogManager.getLogger(CheckExtensionGenerator.class);
-
   static final String PREFERENCE_PLUGIN_XML_FILENAME = "PluginXmlFilename";
   static final String STANDARD_PLUGIN_FILENAME = ICoreConstants.PLUGIN_FILENAME_DESCRIPTOR;
   static final String STANDARD_FRAGMENT_FILENAME = ICoreConstants.FRAGMENT_FILENAME_DESCRIPTOR;
@@ -504,30 +500,18 @@ private void mergeManifest(final CheckCatalog catalog, final IProgressMonitor mo
     final IFile file = PDEProject.getManifest(project);
 
     if (file.exists() && catalog.getGrammar() != null) {
-      InputStream fileContents = null;
-      try {
-        fileContents = file.getContents();
+      try (InputStream fileContents = file.getContents()) {
         MergeableManifest2 manifest = new MergeableManifest2(fileContents, project.getName());
-        fileContents.close();
         manifest.addRequiredBundles(new GrammarHelper(catalog.getGrammar()).getRequiredBundleSymbolicNames());
         if (manifest.isModified()) {
           ByteArrayOutputStream os = new ByteArrayOutputStream();
           manifest.write(os);
-          os.close();
           file.setContents(new ByteArrayInputStream(os.toByteArray()), false, false, monitor);
         }
       } catch (IOException e) {
         throw new WrappedException(e);
       } catch (CoreException e) {
         throw new WrappedException(e);
-      } finally {
-        if (fileContents != null) {
-          try {
-            fileContents.close();
-          } catch (IOException e) {
-            LOGGER.warn("Could not close the Manifest file after modifying it.", e);
-          }
-        }
       }
     }
 
diff --git a/com.avaloq.tools.ddk.xtext.ui/src/com/avaloq/tools/ddk/xtext/ui/editor/model/XtextGMFDocumentProvider.java b/com.avaloq.tools.ddk.xtext.ui/src/com/avaloq/tools/ddk/xtext/ui/editor/model/XtextGMFDocumentProvider.java
index b89eb72d6a..65b69f0158 100644
--- a/com.avaloq.tools.ddk.xtext.ui/src/com/avaloq/tools/ddk/xtext/ui/editor/model/XtextGMFDocumentProvider.java
+++ b/com.avaloq.tools.ddk.xtext.ui/src/com/avaloq/tools/ddk/xtext/ui/editor/model/XtextGMFDocumentProvider.java
@@ -83,7 +83,7 @@ protected boolean setDocumentContent(final IDocument document, final IEditorInpu
   protected void setDocumentContentQuietly(final XtextGMFDocument document, final InputStream contentStream, final String encoding) throws CoreException {
     Reader in = null;
 
-    try {
+    try { // NOPMD UseTryWithResources - conditional close: closes in (if created) or contentStream (caller's)
       String actualEncoding = encoding;
       if (actualEncoding == null) {
         actualEncoding = getDefaultEncoding();
diff --git a/com.avaloq.tools.ddk.xtext.ui/src/com/avaloq/tools/ddk/xtext/ui/editor/templates/ConfigurableTemplateStore.java b/com.avaloq.tools.ddk.xtext.ui/src/com/avaloq/tools/ddk/xtext/ui/editor/templates/ConfigurableTemplateStore.java
index 0b09be3047..80ae7fac7e 100644
--- a/com.avaloq.tools.ddk.xtext.ui/src/com/avaloq/tools/ddk/xtext/ui/editor/templates/ConfigurableTemplateStore.java
+++ b/com.avaloq.tools.ddk.xtext.ui/src/com/avaloq/tools/ddk/xtext/ui/editor/templates/ConfigurableTemplateStore.java
@@ -90,8 +90,7 @@ private void addTemplatesFromFile(final URL templates) {
     if (templates != null) {
       TemplateReaderWriter reader = new TemplateReaderWriter();
       try {
-        InputStream openStream = templates.openStream();
-        try {
+        try (InputStream openStream = templates.openStream()) {
           TemplatePersistenceData[] datas = reader.read(openStream, null);
           int templateCounter = 0;
           for (TemplatePersistenceData data : datas) {
@@ -106,8 +105,6 @@ private void addTemplatesFromFile(final URL templates) {
               internalAdd(data);
             }
           }
-        } finally {
-          openStream.close();
         }
       } catch (IOException e) {
         LOG.error(e);
diff --git a/com.avaloq.tools.ddk.xtext/src/com/avaloq/tools/ddk/xtext/resource/XtextGMFResourceUtil.java b/com.avaloq.tools.ddk.xtext/src/com/avaloq/tools/ddk/xtext/resource/XtextGMFResourceUtil.java
index 8ce7efe13f..bf26950ee8 100644
--- a/com.avaloq.tools.ddk.xtext/src/com/avaloq/tools/ddk/xtext/resource/XtextGMFResourceUtil.java
+++ b/com.avaloq.tools.ddk.xtext/src/com/avaloq/tools/ddk/xtext/resource/XtextGMFResourceUtil.java
@@ -68,7 +68,7 @@ public static byte[] getSeparator(final String encoding) {
   public static byte[] readFullStream(final InputStream input) throws IOException {
     InputStream readStream = null;
     boolean wrappedInput = false;
-    try {
+    try { // NOPMD UseTryWithResources - only closes when we created the wrapper, not the caller's stream
       ByteArrayOutputStream result = new ByteArrayOutputStream();
       byte[] buffer = new byte[INPUT_BUFFER_SIZE];
       if (!(input instanceof BufferedInputStream)) {
diff --git a/ddk-configuration/pmd/ruleset.xml b/ddk-configuration/pmd/ruleset.xml
index cca425c723..cdc4596bc5 100644
--- a/ddk-configuration/pmd/ruleset.xml
+++ b/ddk-configuration/pmd/ruleset.xml
@@ -87,7 +87,6 @@
     <exclude name="PreserveStackTrace"/><!--TODO-->
     <exclude name="UnnecessaryWarningSuppression"/> <!--Experimental, too many false positives-->
     <exclude name="UnusedLocalVariable"/><!--Checkstyle-->
-    <exclude name="UseTryWithResources"/><!--TODO-->
     <exclude name="JUnit5TestShouldBePackagePrivate"/>
   </rule>
   <rule ref="category/java/bestpractices.xml/UnusedFormalParameter">