diff --git a/config/findbugs-exclude.xml b/config/findbugs-exclude.xml
index 9eada5d0f..a1d4247ad 100644
--- a/config/findbugs-exclude.xml
+++ b/config/findbugs-exclude.xml
@@ -42,11 +42,10 @@
       <Class name="com.puppycrawl.tools.checkstyle.api.AuditEvent" />
       <Bug pattern="SE_TRANSIENT_FIELD_NOT_RESTORED" />
     </Match>
-    <Match>
-      <!-- till #596 -->
+<!--    <Match>
       <Class name="com.puppycrawl.tools.checkstyle.Main" />
       <Bug pattern="NP_NULL_ON_SOME_PATH_FROM_RETURN_VALUE" />
-    </Match>
+    </Match>-->
     <Match>
       <!-- till #766 -->
       <Class name="com.puppycrawl.tools.checkstyle.checks.indentation.LineWrappingHandler" />
@@ -77,8 +76,9 @@
       <Bug pattern="NM_CONFUSING" />
     </Match>
     <Match>
-      <!-- till #596 -->
+      <!-- that CLI class so we need system exit code there, but only in main(...) method -->
       <Class name="com.puppycrawl.tools.checkstyle.Main" />
+      <Method name="main" />
       <Bug pattern="DM_EXIT" />
     </Match>
     <Match>
diff --git a/config/pmd.xml b/config/pmd.xml
index 79eaa0e6d..bc2e9d879 100644
--- a/config/pmd.xml
+++ b/config/pmd.xml
@@ -151,10 +151,7 @@
   <rule ref="rulesets/java/junit.xml"/>
   <rule ref="rulesets/java/logging-jakarta-commons.xml"/>
 
-  <rule ref="rulesets/java/logging-java.xml">
-    <!-- till #596 -->
-    <exclude name="AvoidPrintStackTrace"/>
-  </rule>
+  <rule ref="rulesets/java/logging-java.xml"/>
   <rule ref="rulesets/java/logging-java.xml/SystemPrintln">
     <properties>
       <!-- it is ok to use println in CLI class -->
diff --git a/src/main/java/com/puppycrawl/tools/checkstyle/Main.java b/src/main/java/com/puppycrawl/tools/checkstyle/Main.java
index 1fdef9c27..7c4640e82 100644
--- a/src/main/java/com/puppycrawl/tools/checkstyle/Main.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/Main.java
@@ -44,7 +44,8 @@ import org.apache.commons.cli.PosixParser;
 
 /**
  * Wrapper command line program for the Checker.
- * @author Damian Szczepanik (damianszczepanik@github)
+ * @author the original author or authors.
+ *
  **/
 public final class Main
 {
@@ -344,19 +345,23 @@ public final class Main
     {
         // could be replaced with org.apache.commons.io.FileUtils.list() method
         // if only we add commons-io library
-        final List<File> files = Lists.newLinkedList();
+        final List<File> result = Lists.newLinkedList();
 
         if (node.canRead()) {
             if (node.isDirectory()) {
-                for (File element : node.listFiles()) {
-                    files.addAll(listFiles(element));
+                final File[] files = node.listFiles();
+                // listFiles() can return null, so we need to check it
+                if (files != null) {
+                    for (File element : files) {
+                        result.addAll(listFiles(element));
+                    }
                 }
             }
             else if (node.isFile()) {
-                files.add(node);
+                result.add(node);
             }
         }
-        return files;
+        return result;
     }
 
     /** Prints the usage information. **/