[DDLUTILS-227] NullPointerException in ModelBasedResultSetIterator

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 1.1
• Component/s: Core (No specific database), Core - HSQLDB
• Environment: HSQLDB
• Assignee: Thomas Dudziak
• Reporter: Cordeo
• Created: 30/Sep/08 11:48
• Updated: 05/Nov/08 20:29
• Resolved: 05/Nov/08 20:29

Description

The bug is in initFromMetaData(Database)

For subqueries in HSQLDB, tableOfColumn = metaData.getTableName(idx) = "SYSTEM_SUBQUERY", rather than null or "", so the if-block (see below) is executed.
That table, of course is not in the model, so table = model.findTable... will set table to null.
That is correct. But unlike the else-block, tableOfColumn is left unchanged.
This causes the tableName to be wrong, which later on sets the _dynaClass to be null: _dynaClass = model.getDynaClassFor(tableName); // model does not contain a "SYSTEM_SUBQUERY"-table
This finally causes a NullPointerException in the implementation of next():
DynaBean bean = _dynaClass.newInstance();

The solution is simple: Update the tableOfColumn not only in the else-block, but always (only the last few lines changed):

if ((tableOfColumn != null) && (tableOfColumn.length() > 0))
{
_log.debug("Table from metadata: " + tableOfColumn);
// jConnect might return a table name enclosed in quotes
if (tableOfColumn.startsWith("\"") && tableOfColumn.endsWith("\"") && (tableOfColumn.length() > 1))

{ tableOfColumn = tableOfColumn.substring(1, tableOfColumn.length() - 1); }

// the JDBC driver gave us enough meta data info
table = model.findTable(tableOfColumn, _caseSensitive);
}
else

{ _log.debug("Try query hints"); // not enough info in the meta data of the result set, lets try the // user-supplied query hints table = (Table)_preparedQueryHints.get(_caseSensitive ? columnName : columnName.toLowerCase()); }

tableOfColumn = (table == null ? null : table.getName()); // Moved out of the else-block