Add checkstyle rules

build.gradle

@@ -16,6 +16,13 @@ animalsniffer {
     sourceSets = [sourceSets.main]
 }
 
+apply plugin: 'checkstyle'
+
+checkstyle {
+    configFile = 'config/checkstyle.xml' as File
+    toolVersion = '8.10'
+}
+
 group 'org.pgpainless'
 version '0.1-SNAPSHOT'
 

config/checkstyle.xml

@@ -0,0 +1,233 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE module PUBLIC
+        "-//Puppy Crawl//DTD Check Configuration 1.3//EN"
+        "http://www.puppycrawl.com/dtds/configuration_1_3.dtd">
+<module name="Checker">
+
+    <!-- Suppressions -->
+    <module name="SuppressionFilter">
+        <property name="file" value="config/suppressions.xml"/>
+    </module>
+
+    <!-- License Header -->
+    <module name="Header">
+        <property name="headerFile" value="config/checkstyleLicenseHeader.txt"/>
+        <property name="ignoreLines" value="2"/>
+        <property name="fileExtensions" value="java"/>
+    </module>
+
+    <module name="NewlineAtEndOfFile">
+        <property name="lineSeparator" value="lf"/>
+    </module>
+
+    <module name="RegexpSingleline">
+        <!--
+            Matches StringBuilder.append(String) calls where the
+            argument is a String of length one. Those should be replaced
+            with append(char) for performance reasons.
+
+            TODO: This could be more advanced in order to match also
+            - .append("\u1234")
+        -->
+        <property name="format" value="\.append\(&quot;(.|\\.)&quot;\)"/>
+        <property name="message" value="Don&apos;t use StringBuilder.append(String) when you can use StringBuilder.append(char). Solution: Replace double quotes of append&apos;s argument with single quotes."/>
+    </module>
+
+    <!-- Whitespace only lines -->
+    <module name="RegexpSingleline">
+        <property name="format" value="^\s+$"/>
+        <property name="message" value="Line containing only whitespace character(s)"/>
+    </module>
+
+    <!-- Mixed spaces/tabs -->
+    <module name="RegexpSingleline">
+        <!-- We use {2,} instead of + here to address the typical case where a file was written
+           with tabs but javadoc is causing '\t *' -->
+        <property name="format" value="^\t+ {2,}"/>
+        <property name="message" value="Line containing space(s) after tab(s)"/>
+    </module>
+
+    <!-- Trailing whitespaces -->
+    <module name="RegexpSingleline">
+        <!--
+            Explaining the following Regex
+
+                       \s+   $
+                        |    +- End of Line (2)
+                        +- At least one whitespace (1)
+
+            Rationale:
+            Matches trailing whitespace (2) in lines containing at least one (1) non-whitespace character
+        -->
+        <property name="format" value="\s+$"/>
+        <property name="message" value="Line containing trailing whitespace character(s)"/>
+    </module>
+
+    <!-- <module name="RegexpSingleline"> -->
+    <!--   <property name="format" value="fqdn"/> -->
+    <!-- </module> -->
+
+    <!-- Space after // -->
+    <module name="RegexpSingleline">
+        <property name="format" value="^\s*//[^\s]"/>
+        <property name="message" value="Comment start ('//') followed by non-space character. You would not continue after a punctuation without a space, would you?"/>
+    </module>
+
+    <module name="JavadocPackage">
+    </module>
+
+    <module name="TreeWalker">
+        <module name="SuppressionCommentFilter"/>
+        <module name="FinalClass"/>
+        <module name="UnusedImports">
+            <property name="processJavadoc" value="true"/>
+        </module>
+        <module name="AvoidStarImport"/>
+        <module name="IllegalImport"/>
+        <module name="RedundantImport"/>
+        <module name="RedundantModifier"/>
+        <module name="ModifierOrder"/>
+        <module name="UpperEll"/>
+        <module name="ArrayTypeStyle"/>
+        <module name="GenericWhitespace"/>
+        <module name="EmptyStatement"/>
+        <module name="PackageDeclaration"/>
+        <module name="LeftCurly"/>
+
+        <!-- printStackTrace -->
+        <module name="RegexpSinglelineJava">
+            <property name="format" value="printStackTrace"/>
+            <property name="message" value="Usage of printStackTrace. Either rethrow exception, or log using Logger."/>
+            <property name="ignoreComments" value="true"/>
+        </module>
+
+        <!-- println -->
+        <module name="RegexpSinglelineJava">
+            <property name="format" value="println"/>
+            <property name="message" value="Usage of println"/>
+            <property name="ignoreComments" value="true"/>
+        </module>
+
+        <!-- Spaces instead of Tabs -->
+        <module name="RegexpSinglelineJava">
+            <property name="format" value="^\t+"/>
+            <property name="message" value="Indent must not use tab characters. Use space instead."/>
+        </module>
+
+        <module name="JavadocMethod">
+            <!-- TODO stricten those checks -->
+            <property name="scope" value="public"/>
+            <property name="allowUndeclaredRTE" value="true"/>
+            <property name="allowMissingParamTags" value="true"/>
+            <property name="allowMissingThrowsTags" value="true"/>
+            <property name="allowMissingReturnTag" value="true"/>
+            <property name="allowMissingJavadoc" value="true"/>
+            <property name="suppressLoadErrors" value="true"/>
+        </module>
+
+        <module name="JavadocStyle">
+            <property name="scope" value="public"/>
+            <property name="checkEmptyJavadoc" value="true"/>
+            <property name="checkHtml" value="false"/>
+        </module>
+
+        <module name="ParenPad">
+        </module>
+
+        <!-- Whitespace after key tokens -->
+        <module name="NoWhitespaceAfter">
+            <property name="tokens" value="INC
+										 , DEC
+										 , UNARY_MINUS
+										 , UNARY_PLUS
+										 , BNOT, LNOT
+										 , DOT
+										 , ARRAY_DECLARATOR
+										 , INDEX_OP
+										 "/>
+        </module>
+
+        <!-- Whitespace after key words -->
+        <module name="WhitespaceAfter">
+            <property name="tokens" value="TYPECAST
+										 , LITERAL_IF
+										 , LITERAL_ELSE
+										 , LITERAL_WHILE
+										 , LITERAL_DO
+										 , LITERAL_FOR
+										 , DO_WHILE
+										 "/>
+        </module>
+
+        <module name="WhitespaceAround">
+            <property
+                    name="ignoreEnhancedForColon"
+                    value="false"
+            />
+            <!-- Currently disabled tokens: LCURLY, RCURLY, WILDCARD_TYPE, GENERIC_START, GENERIC_END -->
+            <property
+                    name="tokens"
+                    value="ASSIGN
+					 , ARRAY_INIT
+					 , BAND
+					 , BAND_ASSIGN
+					 , BOR
+					 , BOR_ASSIGN
+					 , BSR
+					 , BSR_ASSIGN
+					 , BXOR
+					 , BXOR_ASSIGN
+					 , COLON
+					 , DIV
+					 , DIV_ASSIGN
+					 , DO_WHILE
+					 , EQUAL
+					 , GE
+					 , GT
+					 , LAMBDA
+					 , LAND
+					 , LE
+					 , LITERAL_CATCH
+					 , LITERAL_DO
+					 , LITERAL_ELSE
+					 , LITERAL_FINALLY
+					 , LITERAL_FOR
+					 , LITERAL_IF
+					 , LITERAL_RETURN
+					 , LITERAL_SWITCH
+					 , LITERAL_SYNCHRONIZED
+					 , LITERAL_TRY
+					 , LITERAL_WHILE
+					 , LOR
+					 , LT
+					 , MINUS
+					 , MINUS_ASSIGN
+					 , MOD
+					 , MOD_ASSIGN
+					 , NOT_EQUAL
+					 , PLUS
+					 , PLUS_ASSIGN
+					 , QUESTION
+					 , SL
+					 , SLIST
+					 , SL_ASSIGN
+					 , SR
+					 , SR_ASSIGN
+					 , STAR
+					 , STAR_ASSIGN
+					 , LITERAL_ASSERT
+					 , TYPE_EXTENSION_AND
+					 "/>
+        </module>
+
+        <!--
+        <module name="CustomImportOrder">
+            <property name="customImportOrderRules"
+                      value="STATIC###STANDARD_JAVA_PACKAGE###SPECIAL_IMPORTS###THIRD_PARTY_PACKAGE"/>
+            <property name="specialImportsRegExp" value="^org\.pgpainless\.pgpainless"/>
+            <property name="sortImportsInGroupAlphabetically" value="true"/>
+            <property name="separateLineBetweenGroups" value="true"/>
+        </module>
+        -->
+    </module>
+</module>

config/checkstyleLicenseHeader.txt

@@ -0,0 +1,15 @@
+/*
+ * Copyright 2018 Author Authorsson.
+ *
+ * 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.
+ */

config/suppressions.xml

@@ -0,0 +1,13 @@
+<?xml version="1.0"?>
+<!DOCTYPE suppressions PUBLIC
+        "-//Puppy Crawl//DTD Suppressions 1.1//EN"
+        "http://www.puppycrawl.com/dtds/suppressions_1_1.dtd">
+<suppressions>
+    <!-- GenericWhitespace has some problems with false postive, leave
+it disabled until gradle uses a checkstyle version where this is fixed
+-->
+    <suppress checks="GenericWhitespace"
+              files="Protocol.java" />
+    <!-- Suppress JavadocPackage in the test packages -->
+    <suppress checks="JavadocPackage" files="[\\/]test[\\/]"/>
+</suppressions>

src/main/java/org/pgpainless/pgpainless/algorithm/PublicKeyAlgorithm.java

@@ -28,6 +28,7 @@ public enum PublicKeyAlgorithm {
     ELGAMAL_ENCRYPT (PublicKeyAlgorithmTags.ELGAMAL_ENCRYPT),
     DSA             (PublicKeyAlgorithmTags.DSA),
     /**
+     * EC is deprecated.
      * @deprecated use {@link #ECDH} instead.
      */
     EC              (PublicKeyAlgorithmTags.EC),

src/main/java/org/pgpainless/pgpainless/algorithm/SymmetricKeyAlgorithm.java

@@ -23,6 +23,10 @@ import org.bouncycastle.bcpg.SymmetricKeyAlgorithmTags;
 public enum SymmetricKeyAlgorithm {
 
     NULL            (SymmetricKeyAlgorithmTags.NULL),
+    /**
+     * IDEA is deprecated.
+     * @deprecated use a different algorithm.
+     */
     IDEA            (SymmetricKeyAlgorithmTags.IDEA),
     TRIPLE_DES      (SymmetricKeyAlgorithmTags.TRIPLE_DES),
     CAST5           (SymmetricKeyAlgorithmTags.CAST5),

src/main/java/org/pgpainless/pgpainless/algorithm/package-info.java

@@ -0,0 +1,19 @@
+/*
+ * Copyright 2018 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.
+ */
+/**
+ * Enums which map to OpenPGP's algorithm IDs.
+ */
+package org.pgpainless.pgpainless.algorithm;

src/main/java/org/pgpainless/pgpainless/decryption_verification/DecryptionStreamFactory.java

@@ -50,7 +50,7 @@ import org.pgpainless.pgpainless.algorithm.CompressionAlgorithm;
 import org.pgpainless.pgpainless.algorithm.SymmetricKeyAlgorithm;
 import org.pgpainless.pgpainless.key.SecretKeyRingProtector;
 
-public class DecryptionStreamFactory {
+public final class DecryptionStreamFactory {
 
     private static final Logger LOGGER = Logger.getLogger(DecryptionStreamFactory.class.getName());
     private static final Level LEVEL = Level.FINE;

src/main/java/org/pgpainless/pgpainless/decryption_verification/package-info.java

@@ -0,0 +1,19 @@
+/*
+ * Copyright 2018 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.
+ */
+/**
+ * Classes used to decryption and verification of OpenPGP encrypted / signed data.
+ */
+package org.pgpainless.pgpainless.decryption_verification;

src/main/java/org/pgpainless/pgpainless/encryption_signing/EncryptionStream.java

@@ -49,7 +49,7 @@ import org.pgpainless.pgpainless.decryption_verification.PainlessResult;
  * This class is based upon Jens Neuhalfen's Bouncy-GPG PGPEncryptingStream.
  * @see <a href="https://github.com/neuhalje/bouncy-gpg/blob/master/src/main/java/name/neuhalfen/projects/crypto/bouncycastle/openpgp/encrypting/PGPEncryptingStream.java">Source</a>
  */
-public class EncryptionStream extends OutputStream {
+public final class EncryptionStream extends OutputStream {
 
     private static final Logger LOGGER = Logger.getLogger(EncryptionStream.class.getName());
     private static final Level LEVEL = Level.FINE;

src/main/java/org/pgpainless/pgpainless/encryption_signing/package-info.java

@@ -0,0 +1,19 @@
+/*
+ * Copyright 2018 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.
+ */
+/**
+ * Classes used to encrypt or sign data using OpenPGP.
+ */
+package org.pgpainless.pgpainless.encryption_signing;

src/main/java/org/pgpainless/pgpainless/key/generation/package-info.java

@@ -0,0 +1,19 @@
+/*
+ * Copyright 2018 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.
+ */
+/**
+ * Classes related to OpenPGP key generation.
+ */
+package org.pgpainless.pgpainless.key.generation;

src/main/java/org/pgpainless/pgpainless/key/generation/type/curve/package-info.java

@@ -0,0 +1,19 @@
+/*
+ * Copyright 2018 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.
+ */
+/**
+ * Classes related to elliptic curve cryptography.
+ */
+package org.pgpainless.pgpainless.key.generation.type.curve;

src/main/java/org/pgpainless/pgpainless/key/generation/type/length/ElGamalLength.java

@@ -26,37 +26,37 @@ import java.math.BigInteger;
 public enum ElGamalLength implements KeyLength {
 
     /**
-     * prime: 2^1536 - 2^1472 - 1 + 2^64 * { [2^1406 pi] + 741804 }
+     * prime: 2^1536 - 2^1472 - 1 + 2^64 * { [2^1406 pi] + 741804 }.
      * generator: 2
      */
     _1536(1536, "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E088A67CC74020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245E485B576625E7EC6F44C42E9A637ED6B0BFF5CB6F406B7EDEE386BFB5A899FA5AE9F24117C4B1FE649286651ECE45B3DC2007CB8A163BF0598DA48361C55D39A69163FA8FD24CF5F83655D23DCA3AD961C62F356208552BB9ED529077096966D670C354E4ABC9804F1746C08CA237327FFFFFFFFFFFFFFFF", "2"),
 
     /**
-     * prime: 2^2048 - 2^1984 - 1 + 2^64 * { [2^1918 pi] + 124476 }
+     * prime: 2^2048 - 2^1984 - 1 + 2^64 * { [2^1918 pi] + 124476 }.
      * generator: 2
      */
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
 
     /**
-     * prime: 2^3072 - 2^3008 - 1 + 2^64 * { [2^2942 pi] + 1690314 }
+     * prime: 2^3072 - 2^3008 - 1 + 2^64 * { [2^2942 pi] + 1690314 }.
      * generator: 2
      */
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
 
     /**
-     * prime: 2^4096 - 2^4032 - 1 + 2^64 * { [2^3966 pi] + 240904 }
+     * prime: 2^4096 - 2^4032 - 1 + 2^64 * { [2^3966 pi] + 240904 }.
      * generator: 2
      */
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
 
     /**
-     * prime: 2^6144 - 2^6080 - 1 + 2^64 * { [2^6014 pi] + 929484 }
+     * prime: 2^6144 - 2^6080 - 1 + 2^64 * { [2^6014 pi] + 929484 }.
      * generator: 2
      */
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
 
     /**
-     * prime: 2^8192 - 2^8128 - 1 + 2^64 * { [2^8062 pi] + 4743158 }
+     * prime: 2^8192 - 2^8128 - 1 + 2^64 * { [2^8062 pi] + 4743158 }.
      * generator: 2
      */
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

src/main/java/org/pgpainless/pgpainless/key/generation/type/length/package-info.java

@@ -0,0 +1,19 @@
+/*
+ * Copyright 2018 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.
+ */
+/**
+ * Classes describing the lengths of different public key crypto systems.
+ */
+package org.pgpainless.pgpainless.key.generation.type.length;

src/main/java/org/pgpainless/pgpainless/key/generation/type/package-info.java

@@ -0,0 +1,19 @@
+/*
+ * Copyright 2018 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.
+ */
+/**
+ * Classes describing different OpenPGP key types.
+ */
+package org.pgpainless.pgpainless.key.generation.type;

src/main/java/org/pgpainless/pgpainless/key/package-info.java

@@ -0,0 +1,19 @@
+/*
+ * Copyright 2018 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.
+ */
+/**
+ * Classes related to OpenPGP keys.
+ */
+package org.pgpainless.pgpainless.key;

src/main/java/org/pgpainless/pgpainless/key/selection/key/impl/SignedByMasterKey.java

@@ -1,3 +1,18 @@
+/*
+ * Copyright 2018 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.pgpainless.key.selection.key.impl;
 
 import java.util.Iterator;

src/main/java/org/pgpainless/pgpainless/key/selection/key/impl/package-info.java

@@ -0,0 +1,19 @@
+/*
+ * Copyright 2018 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.
+ */
+/**
+ * Implementations of Key Selection Strategies.
+ */
+package org.pgpainless.pgpainless.key.selection.key.impl;

src/main/java/org/pgpainless/pgpainless/key/selection/key/package-info.java

@@ -0,0 +1,19 @@
+/*
+ * Copyright 2018 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.
+ */
+/**
+ * Different Key Selection Strategies.
+ */
+package org.pgpainless.pgpainless.key.selection.key;

src/main/java/org/pgpainless/pgpainless/key/selection/keyring/impl/package-info.java

@@ -0,0 +1,19 @@
+/*
+ * Copyright 2018 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.
+ */
+/**
+ * Implementations of Key Ring Selection Strategies.
+ */
+package org.pgpainless.pgpainless.key.selection.keyring.impl;

src/main/java/org/pgpainless/pgpainless/key/selection/keyring/package-info.java

@@ -0,0 +1,19 @@
+/*
+ * Copyright 2018 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.
+ */
+/**
+ * Different Key Ring Selection Strategies.
+ */
+package org.pgpainless.pgpainless.key.selection.keyring;

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

@@ -0,0 +1,21 @@
+/*
+ * Copyright 2018 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.
+ */
+/**
+ * PGPainless - Use OpenPGP Painlessly!
+ *
+ * @see <a href="http://pgpainless.org">pgpainless.org</a>
+ */
+package org.pgpainless.pgpainless;

src/main/java/org/pgpainless/pgpainless/symmetric_encryption/SymmetricEncryptorDecryptor.java

@@ -155,8 +155,7 @@ public class SymmetricEncryptorDecryptor {
      * @return compressed data
      * @throws IOException IO is dangerous
      */
-    private static byte[] compress(byte[] clearData, int algorithm) throws IOException
+    private static byte[] compress(byte[] clearData, int algorithm) throws IOException {
-    {
         ByteArrayOutputStream bOut = new ByteArrayOutputStream();
         PGPCompressedDataGenerator comData = new PGPCompressedDataGenerator(algorithm);
         OutputStream cos = comData.open(bOut);

src/main/java/org/pgpainless/pgpainless/symmetric_encryption/package-info.java

@@ -0,0 +1,19 @@
+/*
+ * Copyright 2018 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.
+ */
+/**
+ * Classes related to OpenPGP symmetric encryption.
+ */
+package org.pgpainless.pgpainless.symmetric_encryption;

src/main/java/org/pgpainless/pgpainless/util/MultiMap.java

@@ -64,7 +64,11 @@ public class MultiMap<K, V> {
     }
 
     public void put(K k, V v) {
-        Set<V> values = map.computeIfAbsent(k, k1 -> new HashSet<>());
+        Set<V> values = map.get(k);
+        if (values == null) {
+            values = new HashSet<>();
+            map.put(k, values);
+        }
         values.add(v);
     }
 

src/main/java/org/pgpainless/pgpainless/util/package-info.java

@@ -0,0 +1,19 @@
+/*
+ * Copyright 2018 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.
+ */
+/**
+ * Utility classes.
+ */
+package org.pgpainless.pgpainless.util;

src/test/java/org/pgpainless/pgpainless/SymmetricTest.java

@@ -20,6 +20,8 @@ import static junit.framework.TestCase.assertTrue;
 import java.io.ByteArrayOutputStream;
 import java.io.IOException;
 import java.util.Arrays;
+import java.util.logging.Level;
+import java.util.logging.Logger;
 
 import org.bouncycastle.bcpg.ArmoredOutputStream;
 import org.bouncycastle.openpgp.PGPException;
@@ -28,6 +30,8 @@ import org.pgpainless.pgpainless.algorithm.SymmetricKeyAlgorithm;
 
 public class SymmetricTest extends AbstractPGPainlessTest {
 
+    private static final Logger LOGGER = Logger.getLogger(SymmetricTest.class.getName());
+
     private static final String message = "I grew up with the understanding that the world " +
             "I lived in was one where people enjoyed a sort of freedom " +
             "to communicate with each other in privacy, without it " +
@@ -49,7 +53,7 @@ public class SymmetricTest extends AbstractPGPainlessTest {
         armor.close();
 
         // Print cipher text for validation with GnuPG.
-        System.out.println(new String(out.toByteArray()));
+        LOGGER.log(Level.INFO, new String(out.toByteArray()));
 
         byte[] plain2 = PGPainless.decryptWithPassword(enc, "choose_a_better_password_please".toCharArray());
         assertTrue(Arrays.equals(plain, plain2));