Opening a database with both multi-threaded mode and lock mode 0 (disable…

Opening a database with both multi-threaded mode and lock mode 0 (disable locking) was possible (but only once), even thought it does not work properly.

h2/src/main/org/h2/engine/Database.java

@@ -1935,10 +1935,16 @@ public class Database implements DataHandler {
     }
 
     public void setMultiThreaded(boolean multiThreaded) {
-        if (multiThreaded && multiVersion && this.multiThreaded != multiThreaded) {
+        if (multiThreaded && this.multiThreaded != multiThreaded) {
+            if (multiVersion) {
                 // currently the combination of MVCC and MULTI_THREADED is not supported
                 throw DbException.get(ErrorCode.CANNOT_CHANGE_SETTING_WHEN_OPEN_1, "MVCC & MULTI_THREADED");
             }
+            if (lockMode == 0) {
+                // currently the combination of LOCK_MODE=0 and MULTI_THREADED is not supported
+                throw DbException.get(ErrorCode.CANNOT_CHANGE_SETTING_WHEN_OPEN_1, "LOCK_MODE=0 & MULTI_THREADED");
+            }
+        }
         this.multiThreaded = multiThreaded;
     }