Merge pull request eclipse-edc#9 from agera-edc/feature/6-checkstyle

CI: checkstyle

.github/workflows/check.yaml

@@ -16,3 +16,17 @@ jobs:
         run: |
           terraform fmt -recursive
           git diff --exit-code
+
+      # run Checkstyle explicitly (as opposed to within gradle) due to better reporting capabilities
+      - name: Run Checkstyle
+        if: github.event_name == 'pull_request'
+        uses: nikitasavinov/checkstyle-action@0.6.0
+        with:
+          checkstyle_config: resources/checkstyle-config.xml
+          level: error
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          tool_name: 'checkstyle'
+          checkstyle_version: '9.0'
+          reporter: 'github-pr-check'
+          # Include only violations on added or modified files
+          filter_mode: 'file'

extensions/refresh-catalog/src/main/java/org/eclipse/dataspaceconnector/mvd/RegistrationServiceNodeDirectory.java

@@ -1,3 +1,17 @@
+/*
+ *  Copyright (c) 2022 Microsoft Corporation
+ *
+ *  This program and the accompanying materials are made available under the
+ *  terms of the Apache License, Version 2.0 which is available at
+ *  https://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  SPDX-License-Identifier: Apache-2.0
+ *
+ *  Contributors:
+ *       Microsoft Corporation - initial API and implementation
+ *
+ */
+
 package org.eclipse.dataspaceconnector.mvd;
 
 import org.eclipse.dataspaceconnector.catalog.spi.FederatedCacheNode;

extensions/refresh-catalog/src/test/java/org/eclipse/dataspaceconnector/mvd/RegistrationServiceNodeDirectoryTest.java

@@ -19,7 +19,6 @@
 import org.eclipse.dataspaceconnector.registration.client.api.RegistryApi;
 import org.eclipse.dataspaceconnector.registration.client.models.Participant;
 import org.jetbrains.annotations.NotNull;
-import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.mockito.Mockito;