diff --git a/releasenotes-builder/config/checkstyle.properties b/releasenotes-builder/config/checkstyle.properties
index 4b1a8c040..d728a8bdc 100644
--- a/releasenotes-builder/config/checkstyle.properties
+++ b/releasenotes-builder/config/checkstyle.properties
@@ -1,6 +1,6 @@
-checkstyle.suppressions.file=config/suppressions.xml
 checkstyle.header.file=https://raw.githubusercontent.com/checkstyle/checkstyle/master/config/java.header
-checkstyle.regexp.header.file=https://raw.githubusercontent.com/checkstyle/checkstyle/master/config/java_regexp.header
 checkstyle.importcontrol.file=config/import-control.xml
 checkstyle.importcontroltest.file=config/import-control-test.xml
+checkstyle.suppressions.file=config/suppressions.xml
 checkstyle.suppressions-xpath.file=https://raw.githubusercontent.com/checkstyle/checkstyle/master/config/suppressions-xpath.xml
+checkstyle.regexp.header.file=https://raw.githubusercontent.com/checkstyle/checkstyle/master/config/java_regexp.header
diff --git a/releasenotes-builder/src/main/java/com/github/checkstyle/Main.java b/releasenotes-builder/src/main/java/com/github/checkstyle/Main.java
index 394b0d590..76312ffa1 100644
--- a/releasenotes-builder/src/main/java/com/github/checkstyle/Main.java
+++ b/releasenotes-builder/src/main/java/com/github/checkstyle/Main.java
@@ -47,6 +47,7 @@ private Main() {
      * Entry point.
      *
      * @param args command line arguments.
+     * @noinspection UseOfSystemOutOrSystemErr, CallToSystemExit
      */
     public static void main(String... args) {
         int errorCounter;
@@ -63,7 +64,8 @@ public static void main(String... args) {
                 final Result notesBuilderResult = runGithubNotesBuilder(cliOptions);
                 errorCounter = notesBuilderResult.getErrorMessages().size();
                 if (errorCounter == 0) {
-                    publicationErrors = MainProcess.run(notesBuilderResult.getReleaseNotes(),
+                    publicationErrors = MainProcess.runMainProcess(
+                        notesBuilderResult.getReleaseNotes(),
                             cliOptions);
                 }
             }
@@ -122,6 +124,7 @@ private static Result runGithubNotesBuilder(CliOptions cliOptions)
      * Prints a list of elements in standard out.
      *
      * @param entities a list.
+     * @noinspection UseOfSystemOutOrSystemErr
      */
     private static void printListOf(List<String> entities) {
         System.out.println();
diff --git a/releasenotes-builder/src/main/java/com/github/checkstyle/MainProcess.java b/releasenotes-builder/src/main/java/com/github/checkstyle/MainProcess.java
index 596137563..b42bca639 100644
--- a/releasenotes-builder/src/main/java/com/github/checkstyle/MainProcess.java
+++ b/releasenotes-builder/src/main/java/com/github/checkstyle/MainProcess.java
@@ -71,7 +71,7 @@ private MainProcess() {
      * @throws IOException if I/O error occurs.
      * @throws TemplateException if an error occurs while generating freemarker template.
      */
-    public static List<String> run(Multimap<String, ReleaseNotesMessage> releaseNotes,
+    public static List<String> runMainProcess(Multimap<String, ReleaseNotesMessage> releaseNotes,
             CliOptions cliOptions) throws IOException, TemplateException {
         runPostGeneration(releaseNotes, cliOptions);
         return runPostPublication(cliOptions);
diff --git a/releasenotes-builder/src/main/java/com/github/checkstyle/github/NotesBuilder.java b/releasenotes-builder/src/main/java/com/github/checkstyle/github/NotesBuilder.java
index 3fbb5419a..919aac58c 100644
--- a/releasenotes-builder/src/main/java/com/github/checkstyle/github/NotesBuilder.java
+++ b/releasenotes-builder/src/main/java/com/github/checkstyle/github/NotesBuilder.java
@@ -27,7 +27,6 @@
 import java.util.HashSet;
 import java.util.Optional;
 import java.util.Set;
-import java.util.stream.Collectors;
 
 import org.eclipse.jgit.api.Git;
 import org.eclipse.jgit.api.errors.GitAPIException;
@@ -53,6 +52,7 @@
  *
  * @author Andrei Selkin
  */
+@SuppressWarnings("deprecation")
 public final class NotesBuilder {
 
     /** Array elements separator. */
@@ -85,6 +85,7 @@ private NotesBuilder() {
      * @return a map which represents release notes.
      * @throws IOException if an I/O error occurs.
      * @throws GitAPIException if an error occurs when accessing Git API.
+     * @noinspection UseOfSystemOutOrSystemErr
      */
     public static Result buildResult(String localRepoPath, String authToken, String remoteRepoPath,
         String startRef, String endRef) throws IOException, GitAPIException {
@@ -120,8 +121,7 @@ public static Result buildResult(String localRepoPath, String authToken, String
                 if (issueLabel.isEmpty()) {
                     final String error = String.format(MESSAGE_NO_LABEL,
                         issueNo,
-                        Arrays.stream(Constants.ISSUE_LABELS)
-                                .collect(Collectors.joining(SEPARATOR)),
+                        String.join(SEPARATOR, Constants.ISSUE_LABELS),
                         remoteRepoPath, issueNo);
                     result.addError(error);
                 }
@@ -272,7 +272,7 @@ private static Set<RevCommit> getCommitsForIssue(Set<RevCommit> commits, int iss
      */
     private static String getAuthorsOf(Set<RevCommit> commits) {
         final Set<String> commitAuthors = findCommitAuthors(commits);
-        return commitAuthors.stream().collect(Collectors.joining(SEPARATOR));
+        return String.join(SEPARATOR, commitAuthors);
     }
 
     /**
diff --git a/releasenotes-builder/src/main/java/com/github/checkstyle/publishers/MailingListPublisher.java b/releasenotes-builder/src/main/java/com/github/checkstyle/publishers/MailingListPublisher.java
index fb15c00cb..c8a2e0528 100644
--- a/releasenotes-builder/src/main/java/com/github/checkstyle/publishers/MailingListPublisher.java
+++ b/releasenotes-builder/src/main/java/com/github/checkstyle/publishers/MailingListPublisher.java
@@ -85,12 +85,12 @@ public MailingListPublisher(String postFilename, String username, String passwor
      */
     public void publish() throws MessagingException, IOException {
         final Properties props = System.getProperties();
-        props.put("mail.smtp.starttls.enable", true);
-        props.put("mail.smtp.host", SMTP_HOST);
-        props.put("mail.smtp.user", username);
-        props.put("mail.smtp.password", password);
-        props.put("mail.smtp.port", SMTP_PORT);
-        props.put("mail.smtp.auth", true);
+        props.setProperty("mail.smtp.starttls.enable", String.valueOf(Boolean.TRUE));
+        props.setProperty("mail.smtp.host", SMTP_HOST);
+        props.setProperty("mail.smtp.user", username);
+        props.setProperty("mail.smtp.password", password);
+        props.setProperty("mail.smtp.port", SMTP_PORT);
+        props.setProperty("mail.smtp.auth", String.valueOf(Boolean.TRUE));
 
         final Session session = Session.getInstance(props, null);
         final MimeMessage mimeMessage = new MimeMessage(session);
diff --git a/releasenotes-builder/src/main/java/com/github/checkstyle/publishers/XdocPublisher.java b/releasenotes-builder/src/main/java/com/github/checkstyle/publishers/XdocPublisher.java
index 9a488a902..d40ede062 100644
--- a/releasenotes-builder/src/main/java/com/github/checkstyle/publishers/XdocPublisher.java
+++ b/releasenotes-builder/src/main/java/com/github/checkstyle/publishers/XdocPublisher.java
@@ -72,6 +72,7 @@ public class XdocPublisher {
      * @param releaseNumber release number.
      * @param doPush whether to do push.
      * @param authToken auth token for Github.
+     * @noinspection BooleanParameter
      */
     public XdocPublisher(String postFilename, String localRepoPath, String releaseNumber,
             boolean doPush, String authToken) {
diff --git a/releasenotes-builder/src/test/java/com/github/checkstyle/github/CommitMessageTest.java b/releasenotes-builder/src/test/java/com/github/checkstyle/github/CommitMessageTest.java
index ce7f635e5..4e720e2ec 100644
--- a/releasenotes-builder/src/test/java/com/github/checkstyle/github/CommitMessageTest.java
+++ b/releasenotes-builder/src/test/java/com/github/checkstyle/github/CommitMessageTest.java
@@ -22,6 +22,11 @@
 import org.junit.Assert;
 import org.junit.Test;
 
+/**
+ * Tests commit message structure.
+ *
+ * @noinspection JUnitTestMethodWithNoAssertions
+ */
 public class CommitMessageTest {
 
     @Test
diff --git a/releasenotes-builder/src/test/java/com/github/checkstyle/templates/TemplateProcessorTest.java b/releasenotes-builder/src/test/java/com/github/checkstyle/templates/TemplateProcessorTest.java
index 271c8ac7c..55f4fb653 100644
--- a/releasenotes-builder/src/test/java/com/github/checkstyle/templates/TemplateProcessorTest.java
+++ b/releasenotes-builder/src/test/java/com/github/checkstyle/templates/TemplateProcessorTest.java
@@ -49,6 +49,11 @@
 import com.google.common.collect.ArrayListMultimap;
 import com.google.common.collect.Multimap;
 
+/**
+ * Tests release notes template processing.
+ *
+ * @noinspection JUnitTestMethodWithNoAssertions
+ */
 public class TemplateProcessorTest {
 
     @Rule
@@ -62,7 +67,7 @@ public void setup() throws IOException {
 
     @Test
     public void testGenerateOnlyBreakingCompatibility() throws Exception {
-        final List<String> errors = MainProcess.run(
+        final List<String> errors = MainProcess.runMainProcess(
             createNotes(createAllNotes(), null, null, null, null), createBaseCliOptions()
                 .setGenerateAll(true).build());
 
@@ -76,7 +81,7 @@ public void testGenerateOnlyBreakingCompatibility() throws Exception {
 
     @Test
     public void testGenerateOnlyNewFeature() throws Exception {
-        final List<String> errors = MainProcess.run(
+        final List<String> errors = MainProcess.runMainProcess(
             createNotes(null, createAllNotes(), null, null, null), createBaseCliOptions()
                 .setGenerateAll(true).build());
 
@@ -90,7 +95,7 @@ public void testGenerateOnlyNewFeature() throws Exception {
 
     @Test
     public void testGenerateOnlyBug() throws Exception {
-        final List<String> errors = MainProcess.run(
+        final List<String> errors = MainProcess.runMainProcess(
             createNotes(null, null, createAllNotes(), null, null), createBaseCliOptions()
                 .setGenerateAll(true).build());
 
@@ -104,7 +109,7 @@ public void testGenerateOnlyBug() throws Exception {
 
     @Test
     public void testGenerateOnlyMisc() throws Exception {
-        final List<String> errors = MainProcess.run(
+        final List<String> errors = MainProcess.runMainProcess(
             createNotes(null, null, null, createAllNotes(), null), createBaseCliOptions()
                 .setGenerateAll(true).build());
 
@@ -118,7 +123,7 @@ public void testGenerateOnlyMisc() throws Exception {
 
     @Test
     public void testGenerateOnlyNewModule() throws Exception {
-        final List<String> errors = MainProcess.run(
+        final List<String> errors = MainProcess.runMainProcess(
             createNotes(null, null, null, null, createAllNotes()), createBaseCliOptions()
                 .setGenerateAll(true).build());
 
@@ -132,7 +137,7 @@ public void testGenerateOnlyNewModule() throws Exception {
 
     @Test
     public void testGenerateAll() throws Exception {
-        final List<String> errors = MainProcess.run(
+        final List<String> errors = MainProcess.runMainProcess(
             createNotes(
                 Collections.singletonList(createReleaseNotesMessage("Title 1", "Author 1")),
                 Collections.singletonList(createReleaseNotesMessage(2, "Title 2", "Author 2")),
@@ -151,7 +156,7 @@ public void testGenerateAll() throws Exception {
 
     @Test
     public void testGenerateOnlyXdoc() throws Exception {
-        final List<String> errors = MainProcess.run(
+        final List<String> errors = MainProcess.runMainProcess(
             createNotes(createAllNotes(), null, null, null, null), createBaseCliOptions()
                 .setGenerateXdoc(true).build());
 
@@ -165,7 +170,7 @@ public void testGenerateOnlyXdoc() throws Exception {
 
     @Test
     public void testGenerateOnlyTwitter() throws Exception {
-        final List<String> errors = MainProcess.run(
+        final List<String> errors = MainProcess.runMainProcess(
             createNotes(createAllNotes(), null, null, null, null), createBaseCliOptions()
                 .setGenerateTw(true).build());
 
@@ -179,7 +184,7 @@ public void testGenerateOnlyTwitter() throws Exception {
 
     @Test
     public void testGenerateOnlyRss() throws Exception {
-        final List<String> errors = MainProcess.run(
+        final List<String> errors = MainProcess.runMainProcess(
             createNotes(createAllNotes(), null, null, null, null), createBaseCliOptions()
                 .setGenerateRss(true).build());
 
@@ -193,7 +198,7 @@ public void testGenerateOnlyRss() throws Exception {
 
     @Test
     public void testGenerateOnlyMlist() throws Exception {
-        final List<String> errors = MainProcess.run(
+        final List<String> errors = MainProcess.runMainProcess(
             createNotes(createAllNotes(), null, null, null, null), createBaseCliOptions()
                 .setGenerateMlist(true).build());
 
@@ -211,7 +216,7 @@ public void testGenerateCustomTemplate() throws Exception {
         FileUtils.writeStringToFile(file, "hello world");
         final String template = file.getAbsolutePath();
 
-        final List<String> errors = MainProcess.run(
+        final List<String> errors = MainProcess.runMainProcess(
                 createNotes(createAllNotes(), createAllNotes(), createAllNotes(), createAllNotes(),
                         createAllNotes()),
                 createBaseCliOptions().setGenerateAll(true).setXdocTemplate(template)
@@ -302,15 +307,17 @@ private void assertFile(String expectedName, String actualName) throws IOExcepti
                                 .format(DateTimeFormatter.ofPattern("dd.MM.yyyy", Locale.US)),
                         "XX.XX.XXXX");
 
-        Assert.assertEquals(expectedXdoc, actualXdoc);
+        Assert.assertEquals("Actual filename does not match expected filename",
+            expectedXdoc, actualXdoc);
     }
 
     private void assertFile(String actualName) {
-        Assert.assertFalse(new File(temporaryFolder.getRoot(), actualName).exists());
+        Assert.assertFalse("File does not exist.",
+            new File(temporaryFolder.getRoot(), actualName).exists());
     }
 
     private static String getFileContents(File file) throws IOException {
-        final StringBuilder result = new StringBuilder();
+        final StringBuilder result = new StringBuilder(1024);
 
         try (BufferedReader br = Files.newBufferedReader(file.toPath())) {
             do {