Fix Findbugs errors (#212)

`Findbugs` issues found during
#210

- fix
[errors](https://github.com/hazelcast/hazelcast-wm/actions/runs/18138331537/job/51622684517#step:8:395)
using `volatile`
- disabled Jenkins
[WM-pr-builder](https://jenkins.hazelcast.com/job/WM-pr-builder/) as we
have GH one. I checked and mirrored config. Tomasz thinks Josef might
have started the migration but didn't have a chance to complete

Author: nishaatr

.github/workflows/pr-builder.yaml

@@ -1,4 +1,4 @@
-name: PR builder is just a magic
+name: PR builder
 
 on:
   pull_request_target:
@@ -42,7 +42,7 @@ jobs:
 
       - name: Build
         run: |
-          mvn clean install -DskipTests -B -U
+          mvn clean install -DskipTests -B -P checkstyle -U
 
       - name: Findbugs
         run: |

src/main/java/com/hazelcast/web/HazelcastHttpSession.java

@@ -47,7 +47,7 @@ public class HazelcastHttpSession implements HttpSession {
     private final boolean stickySession;
     private final boolean deferredWrite;
     // true when session is fetched from local cache
-    private boolean keepRemoteActive = true;
+    private volatile boolean keepRemoteActive = true;
     // only true if session is created first time in the cluster
     private volatile boolean clusterWideNew;
     private final Set<String> transientAttributes;
@@ -94,7 +94,7 @@ public void setAttribute(final String name, final Object value) {
         if (!deferredWrite && !transientEntry) {
             try {
                 webFilter.getClusteredSessionService().setAttribute(id, name, value);
-                keepRemoteActive = false;
+                setKeepRemoteActive(false);
                 entry.setDirty(false);
             } catch (HazelcastSerializationException e) {
                 LOGGER.warning("Failed to serialize attribute [" + name + "]:" + e.getMessage(), e);
@@ -110,7 +110,7 @@ public Object getAttribute(final String name) {
         if (cacheEntry == null || cacheEntry.isReload()) {
             try {
                 value = webFilter.getClusteredSessionService().getAttribute(id, name);
-                keepRemoteActive = false;
+                setKeepRemoteActive(false);
                 cacheEntry = new LocalCacheEntry(transientAttributes.contains(name), value);
                 cacheEntry.setReload(false);
                 localCache.put(name, cacheEntry);
@@ -194,7 +194,7 @@ public void removeAttribute(final String name) {
         if (!deferredWrite) {
             try {
                 webFilter.getClusteredSessionService().deleteAttribute(id, name);
-                keepRemoteActive = false;
+                setKeepRemoteActive(false);
                 if (entry != null) {
                     entry.setDirty(false);
                 }
@@ -250,7 +250,7 @@ private void buildLocalCache() {
         Set<Map.Entry<String, Object>> entrySet = null;
         try {
             entrySet = webFilter.getClusteredSessionService().getAttributes(id);
-            keepRemoteActive = false;
+            setKeepRemoteActive(false);
         } catch (Exception e) {
             return;
         }
@@ -287,7 +287,7 @@ void sessionDeferredWrite() {
 
             try {
                 webFilter.getClusteredSessionService().updateAttributes(id, updates);
-                keepRemoteActive = false;
+                setKeepRemoteActive(false);
             } catch (HazelcastSerializationException e) {
                 LOGGER.warning("Failed to serialize session with ID [" + id + "]:" + e.getMessage(), e);
             } catch (Exception e) {
@@ -302,7 +302,7 @@ private Set<String> selectKeys() {
             Set<String> attributeNames = null;
             try {
                 attributeNames = webFilter.getClusteredSessionService().getAttributeNames(id);
-                keepRemoteActive = false;
+                setKeepRemoteActive(false);
             } catch (Exception ignored) {
                 for (Map.Entry<String, LocalCacheEntry> entry : localCache.entrySet()) {
                     if (!entry.getValue().isRemoved() && entry.getValue().getValue() != null) {
@@ -354,7 +354,7 @@ public void updateReloadFlag() {
     public void keepRemoteActive() {
         try {
             webFilter.getClusteredSessionService().getSessionAsync(id);
-            keepRemoteActive = false;
+            setKeepRemoteActive(false);
         } catch (Exception e) {
             LOGGER.warning("Failed to reset the idle-time on cluster for the session with ID [" + id + "]:"
                     + e.getMessage(), e);

src/main/java/com/hazelcast/web/LocalCacheEntry.java

@@ -24,7 +24,7 @@
 public class LocalCacheEntry {
 
     private volatile boolean reload;
-    private boolean removed;
+    private volatile boolean removed;
     private Object value;
     private volatile boolean dirty;
     private final boolean transientEntry;