Fix checkstyle issues

pgpainless-core/src/main/java/org/pgpainless/implementation/package-info.java

@@ -0,0 +1,19 @@
+/*
+ * Copyright 2020 Paul Schaub.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+/**
+ * Implementation factory classes to be able to switch out the underlying crypto engine implementation.
+ */
+package org.pgpainless.implementation;

pgpainless-core/src/main/java/org/pgpainless/key/protection/CallbackBasedKeyringProtector.java

@@ -1,3 +1,18 @@
+/*
+ * Copyright 2020 Paul Schaub.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 package org.pgpainless.key.protection;
 
 import java.util.Map;

pgpainless-core/src/main/java/org/pgpainless/key/protection/SecretKeyRingProtector.java

@@ -26,6 +26,8 @@ import org.bouncycastle.openpgp.operator.PBESecretKeyEncryptor;
 import org.pgpainless.util.Passphrase;
 
 /**
+ * Interface that is used to provide secret key ring encryptors and decryptors.
+ *
  * @deprecated use {@link SecretKeyRingProtector2} instead.
  */
 public interface SecretKeyRingProtector {

pgpainless-core/src/main/java/org/pgpainless/key/protection/SecretKeyRingProtector2.java

@@ -1,3 +1,18 @@
+/*
+ * Copyright 2020 Paul Schaub.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 package org.pgpainless.key.protection;
 
 import org.bouncycastle.openpgp.PGPException;

pgpainless-core/src/main/java/org/pgpainless/key/protection/SecretKeyRingProtectorAdapter.java

@@ -1,3 +1,18 @@
+/*
+ * Copyright 2020 Paul Schaub.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 package org.pgpainless.key.protection;
 
 import org.bouncycastle.openpgp.PGPException;

pgpainless-core/src/main/java/org/pgpainless/key/protection/passphrase_provider/MapBasedPassphraseProvider.java

@@ -18,7 +18,6 @@ package org.pgpainless.key.protection.passphrase_provider;
 import java.util.Map;
 import javax.annotation.Nullable;
 
-import org.bouncycastle.openpgp.PGPSecretKey;
 import org.pgpainless.util.Passphrase;
 
 /**

pgpainless-core/src/test/java/org/pgpainless/key/protection/PassphraseProtectedKeyTest.java

@@ -21,7 +21,6 @@ import static org.junit.jupiter.api.Assertions.assertNull;
 import javax.annotation.Nullable;
 
 import org.bouncycastle.openpgp.PGPException;
-import org.bouncycastle.openpgp.PGPSecretKey;
 import org.junit.jupiter.api.Test;
 import org.pgpainless.key.TestKeys;
 import org.pgpainless.key.protection.passphrase_provider.SecretKeyPassphraseProvider;

pgpainless-sop/src/main/java/org/pgpainless/sop/SopKeyUtil.java

@@ -1,3 +1,18 @@
+/*
+ * Copyright 2020 Paul Schaub.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 package org.pgpainless.sop;
 
 import static org.pgpainless.sop.Print.err_ln;
@@ -17,7 +32,7 @@ public class SopKeyUtil {
     public static List<PGPSecretKeyRing> loadKeysFromFiles(File... files) throws IOException, PGPException {
         List<PGPSecretKeyRing> secretKeyRings = new ArrayList<>();
         for (File file : files) {
-            try(FileInputStream in = new FileInputStream(file)) {
+            try (FileInputStream in = new FileInputStream(file)) {
                 secretKeyRings.add(PGPainless.readKeyRing().secretKeyRing(in));
             } catch (PGPException | IOException e) {
                 err_ln("Could not load secret key " + file.getName() + ": " + e.getMessage());

pgpainless-sop/src/main/java/org/pgpainless/sop/commands/Decrypt.java

@@ -16,7 +16,6 @@
 package org.pgpainless.sop.commands;
 
 import org.bouncycastle.openpgp.PGPException;
-import org.bouncycastle.openpgp.PGPSecretKey;
 import org.bouncycastle.openpgp.PGPSecretKeyRing;
 import org.bouncycastle.openpgp.PGPSecretKeyRingCollection;
 import org.pgpainless.PGPainless;