After we updated H2 from version 2.2.224 to 2.3.230 a StackOverflowException occurs when having multiple SELECT statements in one query, like this:

SELECT c1 FROM table1;
SELECT c2 FROM table1;

We are executing the query like this:

 String sqlStatement = "SELECT c1 FROM table1;\r\nSELECT c2 FROM table1;"
 java.sql.Connection con = // .. get DB connection

try (final Statement testStatement = con.createStatement()) {
    testStatement.execute(sqlStatement);
} catch (SQLException e) {
    // org.h2.jdbc.JdbcSQLNonTransientException: GeneralError; 
} finally {
    //... free DB connection
}

With debugging we found out that the cause is a StackOverflowException:

The reason for that is this change 925a188 (Issue: #4012).

Looking into the code the following happens here:

1. a Command is build in org.h2.command.Parser#prepareCommandList
   with "SELECT c1 FROM table1" as "command" (CommandContainer) and
   "commands" (ArrayList<Prepared>) containing a Select "SELECT c2 FROM table1"
2. calling CommandList.query(int)
3. calls query(int) on the CommandContainer "command"
4. calls org.h2.command.CommandList#executeRemaining()
5. this calls org.h2.command.Command#executeQuery(int, boolean) for each Prepared in ArrayList<Prepared> "commands"
6. this calls org.h2.command.Command#query(int) in line 196
7. since we called executeQuery(int, boolean) of CommandList in step 5 the implementation of CommandList (and not CommandContainer) is used here and we are starting at step 2 again --> endless loop.

I guess the executeQuery(int, boolean) in line 48 of org.h2.command.CommandList#executeRemaining should be called on the created CommandContainer of line 45, but I'm not sure about that.

for (Prepared prepared : commands) {
    CommandContainer commandContainer = new CommandContainer(session, prepared.getSQL(), prepared);
    prepared.prepare();
     if (prepared.isQuery()) {
        executeQuery(0, false); // --> instead use commandContainer.executeQuery(0, false);
    } else {
        commandContainer.executeUpdate(null);
     }
}

Hope this helps!

Regards, jacquipre.