src/main/java/com/conveyal/gtfs/loader/JdbcGtfsSnapshotter.java
private boolean tableExists(String namespace, String tableName) {
        // Preempt SQL check with null check of either namespace or table name.
        if (namespace == null || tableName == null) return false;
        try {
            // This statement is postgres-specific.
            PreparedStatement tableExistsStatement = connection.prepareStatement(
                "SELECT EXISTS (SELECT 1 FROM information_schema.tables WHERE table_schema = ? AND table_name = ?)"
            );
            tableExistsStatement.setString(1, namespace);
            tableExistsStatement.setString(2, tableName);
            ResultSet resultSet = tableExistsStatement.executeQuery();
            resultSet.next();
            return resultSet.getBoolean(1);
        } catch (SQLException e) {
            e.printStackTrace();
            return false;
        }
    }
private boolean tableExists(String namespace, String tableName) {
        // Preempt SQL check with null check of either namespace or table name.
        if (namespace == null || tableName == null) return false;
        try {
            // This statement is postgres-specific.
            PreparedStatement tableExistsStatement = connection.prepareStatement(
                "SELECT EXISTS (SELECT 1 FROM information_schema.tables WHERE table_schema = ? AND table_name = ?)"
            );
            tableExistsStatement.setString(1, namespace);
            tableExistsStatement.setString(2, tableName);
            ResultSet resultSet = tableExistsStatement.executeQuery();
            resultSet.next();
            return resultSet.getBoolean(1);
        } catch (SQLException e) {
            e.printStackTrace();
            return false;
        }
    }
Helper method to determine if a table exists within a namespace.