diff --git a/src/main/java/com/puppycrawl/tools/checkstyle/api/AbstractFileSetCheck.java b/src/main/java/com/puppycrawl/tools/checkstyle/api/AbstractFileSetCheck.java
index 54541f0505dc..5888a7312226 100644
--- a/src/main/java/com/puppycrawl/tools/checkstyle/api/AbstractFileSetCheck.java
+++ b/src/main/java/com/puppycrawl/tools/checkstyle/api/AbstractFileSetCheck.java
@@ -37,8 +37,12 @@ public abstract class AbstractFileSetCheck
     extends AbstractViolationReporter
     implements FileSetCheck {
 
-    /** Collects the error messages. */
-    private final SortedSet<LocalizedMessage> messageCollector = new TreeSet<>();
+    /**
+     * Collects the error messages.
+     * @noinspection ThreadLocalNotStaticFinal
+     */
+    private final ThreadLocal<SortedSet<LocalizedMessage>> messageCollector =
+            ThreadLocal.withInitial(TreeSet::new);
 
     /** The dispatcher errors are fired to. */
     private MessageDispatcher messageDispatcher;
@@ -73,12 +77,12 @@ public void beginProcessing(String charset) {
     @Override
     public final SortedSet<LocalizedMessage> process(File file, FileText fileText)
             throws CheckstyleException {
-        messageCollector.clear();
+        messageCollector.get().clear();
         // Process only what interested in
         if (CommonUtils.matchesFileExtension(file, fileExtensions)) {
             processFiltered(file, fileText);
         }
-        return new TreeSet<>(messageCollector);
+        return new TreeSet<>(messageCollector.get());
     }
 
     @Override
@@ -139,7 +143,7 @@ public final void setFileExtensions(String... extensions) {
      * @param messages the sorted set of {@link LocalizedMessage}.
      */
     protected final void addMessages(SortedSet<LocalizedMessage> messages) {
-        messageCollector.addAll(messages);
+        messageCollector.get().addAll(messages);
     }
 
     @Override
@@ -150,7 +154,7 @@ public final void log(int line, String key, Object... args) {
     @Override
     public final void log(int lineNo, int colNo, String key,
             Object... args) {
-        messageCollector.add(
+        messageCollector.get().add(
                 new LocalizedMessage(lineNo,
                         colNo,
                         getMessageBundle(),
@@ -169,8 +173,8 @@ public final void log(int lineNo, int colNo, String key,
      * @param fileName the audited file
      */
     protected final void fireErrors(String fileName) {
-        final SortedSet<LocalizedMessage> errors = new TreeSet<>(messageCollector);
-        messageCollector.clear();
+        final SortedSet<LocalizedMessage> errors = new TreeSet<>(messageCollector.get());
+        messageCollector.get().clear();
         messageDispatcher.fireErrors(fileName, errors);
     }
 }