Fix SpotBugs errors

- [ERROR] Medium: Class
org.apache.commons.io.monitor.FileAlterationObserver defines
non-transient non-serializable instance field fileFilter
[org.apache.commons.io.monitor.FileAlterationObserver] In
FileAlterationObserver.java SE_BAD_FIELD
- [ERROR] Medium: Class
org.apache.commons.io.monitor.FileAlterationObserver defines
non-transient non-serializable instance field listeners
[org.apache.commons.io.monitor.FileAlterationObserver] In
FileAlterationObserver.java SE_BAD_FIELD

src/changes/changes.xml

@@ -59,6 +59,8 @@ The <action> type attribute can be add,update,fix,remove.
       <action dev="ggregory" type="fix" due-to="Gary Gregory">Fix SpotBugs error: Class org.apache.commons.io.filefilter.DelegateFileFilter defines non-transient non-serializable instance field fileFilter [org.apache.commons.io.filefilter.DelegateFileFilter] In DelegateFileFilter.java SE_BAD_FIELD.</action>
       <action dev="ggregory" type="fix" due-to="Gary Gregory">Fix SpotBugs error: Class org.apache.commons.io.filefilter.DelegateFileFilter defines non-transient non-serializable instance field fileNameFilter [org.apache.commons.io.filefilter.DelegateFileFilter] In DelegateFileFilter.java SE_BAD_FIELD.</action>
       <action dev="ggregory" type="fix" due-to="Gary Gregory">Fix SpotBugs error: org.apache.commons.io.function.IOStream$1.next() cannot throw NoSuchElementException [org.apache.commons.io.function.IOStream$1] At IOStream.java:[line 98] IT_NO_SUCH_ELEMENT.</action>
+      <action dev="ggregory" type="fix" due-to="Gary Gregory">Fix SpotBugs error: Class org.apache.commons.io.monitor.FileAlterationObserver defines non-transient non-serializable instance field fileFilter [org.apache.commons.io.monitor.FileAlterationObserver] In FileAlterationObserver.java SE_BAD_FIELD.</action>
+      <action dev="ggregory" type="fix" due-to="Gary Gregory">Fix SpotBugs error: Class org.apache.commons.io.monitor.FileAlterationObserver defines non-transient non-serializable instance field listeners [org.apache.commons.io.monitor.FileAlterationObserver] In FileAlterationObserver.java SE_BAD_FIELD.</action>
       <!-- UPDATE -->
       <action dev="ggregory" type="update" due-to="Gary Gregory">Bump org.codehaus.mojo:exec-maven-plugin from 3.1.0 to 3.1.1 #512.</action>
       <action dev="ggregory" type="update" due-to="Gary Gregory">Bump commons-lang3 from 3.13.0 to 3.14.0.</action>      

src/main/java/org/apache/commons/io/monitor/FileAlterationObserver.java

@@ -128,9 +128,9 @@
 public class FileAlterationObserver implements Serializable {
 
     private static final long serialVersionUID = 1185122225658782848L;
-    private final List<FileAlterationListener> listeners = new CopyOnWriteArrayList<>();
+    private transient final List<FileAlterationListener> listeners = new CopyOnWriteArrayList<>();
     private final FileEntry rootEntry;
-    private final FileFilter fileFilter;
+    private transient final FileFilter fileFilter;
     private final Comparator<File> comparator;
 
     /**