#fixed code
                                private static void parseAlterColumn(final Parser parser,
            final PgTable table) {
        parser.expectOptional("COLUMN");

        final String columnName = parser.parseIdentifier();

        if (parser.expectOptional("SET")) {
            if (parser.expectOptional("STATISTICS")) {
                final PgColumn column = table.getColumn(columnName);
                column.setStatistics(parser.parseInteger());
            } else if (parser.expectOptional("DEFAULT")) {
                final String defaultValue = parser.getExpression();

                if (table.containsColumn(columnName)) {
                    final PgColumn column = table.getColumn(columnName);
                    column.setDefaultValue(defaultValue);
                } else {
                    throw new ParserException("Cannot find column '"
                            + columnName + " 'in table '" + table.getName()
                            + "'");
                }
            } else if (parser.expectOptional("STORAGE")) {
                final PgColumn column = table.getColumn(columnName);

                if (parser.expectOptional("PLAIN")) {
                    column.setStorage("PLAIN");
                } else if (parser.expectOptional("EXTERNAL")) {
                    column.setStorage("EXTERNAL");
                } else if (parser.expectOptional("EXTENDED")) {
                    column.setStorage("EXTENDED");
                } else if (parser.expectOptional("MAIN")) {
                    column.setStorage("MAIN");
                } else {
                    parser.throwUnsupportedCommand();
                }
            } else {
                parser.throwUnsupportedCommand();
            }
        } else {
            parser.throwUnsupportedCommand();
        }
    }
#vulnerable code 
                                private static void parseAlterColumn(final Parser parser,
            final PgTable table) {
        parser.expectOptional("COLUMN");

        final String columnName = parser.parseIdentifier();

        if (parser.expectOptional("SET")) {
            if (parser.expectOptional("STATISTICS")) {
                final PgColumn col = table.getColumn(columnName);
                col.setStatistics(parser.parseInteger());
            } else if (parser.expectOptional("DEFAULT")) {
                final String defaultValue = parser.getExpression();

                if (table.containsColumn(columnName)) {
                    final PgColumn column = table.getColumn(columnName);
                    column.setDefaultValue(defaultValue);
                } else {
                    throw new ParserException("Cannot find column '"
                            + columnName + " 'in table '" + table.getName()
                            + "'");
                }
            } else {
                parser.throwUnsupportedCommand();
            }
        } else {
            parser.throwUnsupportedCommand();
        }
    } 
                            #location 10 
                            #vulnerability type NULL_DEREFERENCE