Workaround for hanging JavaMail close

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

@@ -126,6 +126,7 @@ public class ServiceSynchronize extends LifecycleService {
     private static final int CONNECT_BACKOFF_START = 8; // seconds
     private static final int CONNECT_BACKOFF_MAX = 1024; // seconds (1024 sec ~ 17 min)
     private static final long STORE_NOOP_INTERVAL = 9 * 60 * 1000L; // ms
+    private static final long STORE_CLOSE_TIMEOUT = 20 * 1000L; // ms
     private static final int ATTACHMENT_AUTO_DOWNLOAD_SIZE = 32 * 1024; // bytes
 
     static final String ACTION_SYNCHRONIZE_FOLDER = BuildConfig.APPLICATION_ID + ".SYNCHRONIZE_FOLDER";
@@ -792,10 +793,25 @@ public class ServiceSynchronize extends LifecycleService {
                 for (EntityFolder folder : folders.keySet())
                     db.folder().setFolderState(folder.id, "closing");
                 try {
-                    // This can take some time
-                    istore.close();
-                } catch (MessagingException ex) {
-                    Log.w(Helper.TAG, account.name + " " + ex + "\n" + Log.getStackTraceString(ex));
+                    Thread t = new Thread(new Runnable() {
+                        @Override
+                        public void run() {
+                            try {
+                                EntityLog.log(ServiceSynchronize.this, account.name + " store closing");
+                                istore.close();
+                                EntityLog.log(ServiceSynchronize.this, account.name + " store closed");
+                            } catch (Throwable ex) {
+                                Log.w(Helper.TAG, account.name + " " + ex + "\n" + Log.getStackTraceString(ex));
+                            }
+                        }
+                    });
+                    t.start();
+                    try {
+                        t.join(STORE_CLOSE_TIMEOUT);
+                    } catch (InterruptedException ex) {
+                        Log.w(Helper.TAG, account.name + " Close timeout");
+                        t.interrupt();
+                    }
                 } finally {
                     EntityLog.log(this, account.name + " closed");
                     db.account().setAccountState(account.id, null);