diff --git a/plugins/org.eclipse.n4js.cli/src/org/eclipse/n4js/cli/N4jscModule.java b/plugins/org.eclipse.n4js.cli/src/org/eclipse/n4js/cli/N4jscModule.java
index a6e22a2140..8581ef2591 100644
--- a/plugins/org.eclipse.n4js.cli/src/org/eclipse/n4js/cli/N4jscModule.java
+++ b/plugins/org.eclipse.n4js.cli/src/org/eclipse/n4js/cli/N4jscModule.java
@@ -15,7 +15,6 @@
 /**
  * Use this class to override bindings for the cli use case.
  */
-@SuppressWarnings({ "javadoc" })
 public class N4jscModule extends AbstractGenericModule {
 
 	// public Class<? extends DefaultBuildRequestFactory> bindDocumentExtensions() {
diff --git a/plugins/org.eclipse.n4js.json.ide/src/org/eclipse/n4js/json/ide/codeActions/JSONCodeActionService.java b/plugins/org.eclipse.n4js.json.ide/src/org/eclipse/n4js/json/ide/codeActions/JSONCodeActionService.java
index 3fd6c8e277..086c71e830 100644
--- a/plugins/org.eclipse.n4js.json.ide/src/org/eclipse/n4js/json/ide/codeActions/JSONCodeActionService.java
+++ b/plugins/org.eclipse.n4js.json.ide/src/org/eclipse/n4js/json/ide/codeActions/JSONCodeActionService.java
@@ -54,7 +54,7 @@ public List<Either<Command, CodeAction>> getCodeActions(Options options) {
 		if (options.getCodeActionParams() != null && options.getCodeActionParams().getContext() != null) {
 			List<Diagnostic> diagnostics = options.getCodeActionParams().getContext().getDiagnostics();
 			for (Diagnostic diag : diagnostics) {
-				if (IssueCodes.NON_EXISTING_PROJECT.equals(diag.getCode().getLeft())) {
+				if (IssueCodes.NON_EXISTING_PROJECT.name().equals(diag.getCode().getLeft())) {
 					Command cmd = createInstallNpmCommand(options, diag);
 					if (cmd != null) {
 						result.add(Either.forLeft(cmd));
diff --git a/plugins/org.eclipse.n4js.utils/src/org/eclipse/n4js/utils/languages/N4LanguageUtils.java b/plugins/org.eclipse.n4js.utils/src/org/eclipse/n4js/utils/languages/N4LanguageUtils.java
index e5c2cdbae6..cb72918da2 100644
--- a/plugins/org.eclipse.n4js.utils/src/org/eclipse/n4js/utils/languages/N4LanguageUtils.java
+++ b/plugins/org.eclipse.n4js.utils/src/org/eclipse/n4js/utils/languages/N4LanguageUtils.java
@@ -39,7 +39,6 @@
  */
 public class N4LanguageUtils {
 
-	@SuppressWarnings("javadoc")
 	public static final class ParseResult<T extends EObject> {
 		/** The AST. May be <code>null</code> in case of error. */
 		public final T ast;
diff --git a/plugins/org.eclipse.n4js.utils/src/org/eclipse/n4js/xtext/serializer/SerializerPatchModule.java b/plugins/org.eclipse.n4js.utils/src/org/eclipse/n4js/xtext/serializer/SerializerPatchModule.java
index 593915805c..5c3684a250 100644
--- a/plugins/org.eclipse.n4js.utils/src/org/eclipse/n4js/xtext/serializer/SerializerPatchModule.java
+++ b/plugins/org.eclipse.n4js.utils/src/org/eclipse/n4js/xtext/serializer/SerializerPatchModule.java
@@ -20,7 +20,7 @@
 
 import com.google.inject.AbstractModule;
 
-@SuppressWarnings({ "javadoc", "restriction" })
+@SuppressWarnings("restriction")
 public class SerializerPatchModule extends AbstractModule {
 
 	@Override
diff --git a/testhelpers/org.eclipse.n4js.cli.tests.helper/src/org/eclipse/n4js/cli/N4jscTestFactory.java b/testhelpers/org.eclipse.n4js.cli.tests.helper/src/org/eclipse/n4js/cli/N4jscTestFactory.java
index a08b68467d..cfebacc5fd 100644
--- a/testhelpers/org.eclipse.n4js.cli.tests.helper/src/org/eclipse/n4js/cli/N4jscTestFactory.java
+++ b/testhelpers/org.eclipse.n4js.cli.tests.helper/src/org/eclipse/n4js/cli/N4jscTestFactory.java
@@ -27,7 +27,6 @@
 public class N4jscTestFactory extends N4jscFactory {
 
 	/** An {@link N4jscFactory} and related global state. */
-	@SuppressWarnings("javadoc")
 	public static final class State {
 		public final N4jscFactory n4jscFactory;
 		public final GlobalStateMemento globalState;
diff --git a/testhelpers/org.eclipse.n4js.tests.helper/src/org/eclipse/n4js/N4JSInjectorProviderWithIndex.java b/testhelpers/org.eclipse.n4js.tests.helper/src/org/eclipse/n4js/N4JSInjectorProviderWithIndex.java
index 6b860408d0..50de556920 100644
--- a/testhelpers/org.eclipse.n4js.tests.helper/src/org/eclipse/n4js/N4JSInjectorProviderWithIndex.java
+++ b/testhelpers/org.eclipse.n4js.tests.helper/src/org/eclipse/n4js/N4JSInjectorProviderWithIndex.java
@@ -21,7 +21,6 @@ public N4JSInjectorProviderWithIndex() {
 		super(new EagerResourceSetModule());
 	}
 
-	@SuppressWarnings("javadoc")
 	public static class EagerResourceSetModule extends BaseTestModule {
 		public Class<? extends IResourceDescriptions> bindResourceDescriptions() {
 			return EagerResourceSetBasedResourceDescriptions.class;
diff --git a/tests/org.eclipse.n4js.ide.tests/src/org/eclipse/n4js/ide/tests/builder/YarnProjectDuplicateNames.java b/tests/org.eclipse.n4js.ide.tests/src/org/eclipse/n4js/ide/tests/builder/YarnProjectDuplicateNames.java
index 69f0c555a9..71d345d25e 100644
--- a/tests/org.eclipse.n4js.ide.tests/src/org/eclipse/n4js/ide/tests/builder/YarnProjectDuplicateNames.java
+++ b/tests/org.eclipse.n4js.ide.tests/src/org/eclipse/n4js/ide/tests/builder/YarnProjectDuplicateNames.java
@@ -28,7 +28,7 @@
 /**
  * Test two cases of projects with the same project name within a yarn setup
  */
-@SuppressWarnings({ "javadoc", "unchecked" })
+@SuppressWarnings("unchecked")
 public class YarnProjectDuplicateNames extends AbstractIncrementalBuilderTest {
 
 	private static Map<String, Map<String, String>> testData1 = Map.of(
diff --git a/tests/org.eclipse.n4js.ide.tests/src/org/eclipse/n4js/ide/tests/xtext/server/ChunkedResourceDescriptionsTest.java b/tests/org.eclipse.n4js.ide.tests/src/org/eclipse/n4js/ide/tests/xtext/server/ChunkedResourceDescriptionsTest.java
index b2cf12d7a5..7e86e95f6e 100644
--- a/tests/org.eclipse.n4js.ide.tests/src/org/eclipse/n4js/ide/tests/xtext/server/ChunkedResourceDescriptionsTest.java
+++ b/tests/org.eclipse.n4js.ide.tests/src/org/eclipse/n4js/ide/tests/xtext/server/ChunkedResourceDescriptionsTest.java
@@ -34,7 +34,7 @@
  * Performance test for resource description implementations.
  */
 @Ignore("TODO Implement a way to make this a real test with assertions on the timing")
-@SuppressWarnings({ "javadoc", "restriction" })
+@SuppressWarnings("restriction")
 public class ChunkedResourceDescriptionsTest {
 
 	@Test
diff --git a/tests/org.eclipse.n4js.ui.tests/src/org/eclipse/n4js/tests/dirtystate/BuilderParticipantIdeTest.java b/tests/org.eclipse.n4js.ui.tests/src/org/eclipse/n4js/tests/dirtystate/BuilderParticipantIdeTest.java
index 250b8081c0..484e21ace7 100644
--- a/tests/org.eclipse.n4js.ui.tests/src/org/eclipse/n4js/tests/dirtystate/BuilderParticipantIdeTest.java
+++ b/tests/org.eclipse.n4js.ui.tests/src/org/eclipse/n4js/tests/dirtystate/BuilderParticipantIdeTest.java
@@ -158,7 +158,6 @@ public void testMethodRenamedInSuperClassOfClassThatIsUsedToCallTheMethod() thro
 	 * 07. Brother should have no error markers
 	 */
 	//@formatter:on
-	@SuppressWarnings("resource")
 	@Test
 	// TODO: while running there is a java.lang.IndexOutOfBoundsException: Index: 2, Size: 0 at at
 	// org.eclipse.n4js.resource.N4JSResource.getEncodedURI(N4JSResource.java:446)
diff --git a/tests/org.eclipse.n4js.ui.tests/src/org/eclipse/n4js/tests/dirtystate/testdata/StaticTestFiles.java b/tests/org.eclipse.n4js.ui.tests/src/org/eclipse/n4js/tests/dirtystate/testdata/StaticTestFiles.java
index 76bb242f67..03014d806f 100644
--- a/tests/org.eclipse.n4js.ui.tests/src/org/eclipse/n4js/tests/dirtystate/testdata/StaticTestFiles.java
+++ b/tests/org.eclipse.n4js.ui.tests/src/org/eclipse/n4js/tests/dirtystate/testdata/StaticTestFiles.java
@@ -10,7 +10,6 @@
  */
 package org.eclipse.n4js.tests.dirtystate.testdata;
 
-@SuppressWarnings("unused")
 public class StaticTestFiles {
 
 	public static String moduleFolder() {