Use isEmpty().

Author: Gary Gregory

src/main/java/org/apache/commons/io/FileCleaningTracker.java

@@ -215,7 +215,7 @@ private final class Reaper extends Thread {
         @Override
         public void run() {
             // thread exits when exitWhenFinished is true and there are no more tracked objects
-            while (exitWhenFinished == false || trackers.size() > 0) {
+            while (exitWhenFinished == false || !trackers.isEmpty()) {
                 try {
                     // Wait for a tracker to remove.
                     final Tracker tracker = (Tracker) q.remove(); // cannot return null