Exception handling improvements

Assorted minor changes

h2/src/main/org/h2/mvstore/MVStore.java

@@ -511,16 +511,18 @@ public class MVStore {
             M map = (M) getMap(id);
             if (map == null) {
                 String configAsString = meta.get(MVMap.getMapKey(id));
-                if(configAsString != null) {
-                    HashMap<String, Object> config =
-                            new HashMap<String, Object>(DataUtils.parseMap(configAsString));
-                    config.put("id", id);
-                    map = builder.create(this, config);
-                    map.init();
-                    long root = getRootPos(meta, id);
-                    map.setRootPos(root, lastStoredVersion);
-                    maps.put(id, map);
+                HashMap<String, Object> config;
+                if (configAsString != null) {
+                    config = new HashMap<String, Object>(DataUtils.parseMap(configAsString));
+                } else {
+                    config = new HashMap<>();
                 }
+                config.put("id", id);
+                map = builder.create(this, config);
+                map.init();
+                long root = getRootPos(meta, id);
+                map.setRootPos(root, lastStoredVersion);
+                maps.put(id, map);
             }
             return map;
         } finally {

h2/src/main/org/h2/mvstore/db/MVTableEngine.java

@@ -246,21 +246,6 @@ public class MVTableEngine implements TableEngine {
             store.closeImmediately();
         }
 
-        /**
-         * Commit all transactions that are in the committing state, and
-         * rollback all open transactions.
-         */
-        public void initTransactions() {
-            List<Transaction> list = transactionStore.getOpenTransactions();
-            for (Transaction t : list) {
-                if (t.getStatus() == Transaction.STATUS_COMMITTED) {
-                    t.commit();
-                } else if (t.getStatus() != Transaction.STATUS_PREPARED) {
-                    t.rollback();
-                }
-            }
-        }
-
         /**
          * Remove all temporary maps.
          *

h2/src/main/org/h2/mvstore/tx/TransactionStore.java

@@ -147,14 +147,6 @@ public class TransactionStore {
      */
     public void init() {
         if (!init) {
-            // remove all temporary maps
-            for (String mapName : store.getMapNames()) {
-                if (mapName.startsWith("temp.")) {
-                    MVMap<Object, Integer> temp = openTempMap(mapName);
-                    store.removeMap(temp);
-                }
-            }
-
             for (String mapName : store.getMapNames()) {
                 if (mapName.startsWith(UNDO_LOG_NAME_PEFIX)) {
                     if (store.hasData(mapName)) {
@@ -165,13 +157,15 @@ public class TransactionStore {
                             int status;
                             String name;
                             if (data == null) {
-                                status = mapName.charAt(UNDO_LOG_NAME_PEFIX.length()) == UNDO_LOG_OPEN ?
-                                        Transaction.STATUS_OPEN : Transaction.STATUS_COMMITTED;
+                                status = Transaction.STATUS_OPEN;
                                 name = null;
                             } else {
                                 status = (Integer) data[0];
                                 name = (String) data[1];
                             }
+                            if (mapName.charAt(UNDO_LOG_NAME_PEFIX.length()) == UNDO_LOG_COMMITTED) {
+                                status = Transaction.STATUS_COMMITTED;
+                            }
                             MVMap<Long, Object[]> undoLog = store.openMap(mapName, undoLogBuilder);
                             undoLogs[transactionId] = undoLog;
                             Long lastUndoKey = undoLog.lastKey();
@@ -187,6 +181,21 @@ public class TransactionStore {
         }
     }
 
+    /**
+     * Commit all transactions that are in the committed state, and
+     * rollback all open transactions.
+     */
+    public void endLeftoverTransactions() {
+        List<Transaction> list = getOpenTransactions();
+        for (Transaction t : list) {
+            if (t.getStatus() == Transaction.STATUS_COMMITTED) {
+                t.commit();
+            } else if (t.getStatus() != Transaction.STATUS_PREPARED) {
+                t.rollback();
+            }
+        }
+    }
+
     /**
      * Set the maximum transaction id, after which ids are re-used. If the old
      * transaction is still in use when re-using an old id, the new transaction