Folder NOOP

.idea/misc.xml

@@ -25,7 +25,7 @@
       </value>
     </option>
   </component>
-  <component name="ProjectRootManager" version="2" languageLevel="JDK_1_7" project-jdk-name="1.8" project-jdk-type="JavaSDK">
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_1_8" project-jdk-name="1.8" project-jdk-type="JavaSDK">
     <output url="file://$PROJECT_DIR$/build/classes" />
   </component>
   <component name="ProjectType">

app/src/main/java/eu/faircode/email/ServiceSynchronize.java

@@ -52,10 +52,12 @@ import android.text.TextUtils;
 import android.util.Log;
 
 import com.sun.mail.iap.ConnectionException;
+import com.sun.mail.iap.ProtocolException;
 import com.sun.mail.imap.AppendUID;
 import com.sun.mail.imap.IMAPFolder;
 import com.sun.mail.imap.IMAPMessage;
 import com.sun.mail.imap.IMAPStore;
+import com.sun.mail.imap.protocol.IMAPProtocol;
 import com.sun.mail.util.FolderClosedIOException;
 import com.sun.mail.util.MailConnectException;
 
@@ -1024,12 +1026,24 @@ public class ServiceSynchronize extends LifecycleService {
                                 if (!istore.isConnected())
                                     throw new StoreClosedException(istore);
 
-                                for (EntityFolder folder : folders.keySet())
+                                for (final EntityFolder folder : folders.keySet()) {
+                                    IMAPFolder ifolder = folders.get(folder);
                                     if (capIdle) {
-                                        if (!folders.get(folder).isOpen())
-                                            throw new FolderClosedException(folders.get(folder));
+                                        try {
+                                            ifolder.doCommand(new IMAPFolder.ProtocolCommand() {
+                                                public Object doCommand(IMAPProtocol p)
+                                                        throws ProtocolException {
+                                                    Log.i(Helper.TAG, folder.name + " do noop");
+                                                    p.simpleCommand("NOOP", null);
+                                                    return null;
+                                                }
+                                            });
+                                        } catch (MessagingException ex) {
+                                            throw new FolderClosedException(ifolder, "NOOP", ex);
+                                        }
                                     } else
-                                        synchronizeMessages(account, folder, folders.get(folder), state);
+                                        synchronizeMessages(account, folder, ifolder, state);
+                                }
                             }
 
                         }