JDBC Sqlite trying to get Nullable Columns

I am trying to retrieve all nullable collumns from an SQLite Database in java.

I don't know why JDBC is returning that only the Primary Key is Not NULL when there are two columns with not nullproperty.

CREATE TABLE `univDB` (
        `x` INTEGER NOT NULL PRIMARY KEY AUTOINCREMENT,
        `FirstColumn`   TEXT NOT NULL,
        `SecondColumn`  TEXT
    );

and when I run the following code:

    ResultSet rs = stmt.executeQuery("SELECT * FROM "+table);

    for (int i=1; i<= rs.getMetaData().getColumnCount(); i++) {
            System.out.println("NULLABLE column "+i+" "+rs.getMetaData().isNullable(i));
            if (ResultSetMetaData.columnNoNulls == rs.getMetaData().isNullable(i)) {
                System.out.println("Column Not Null "+rs.getMetaData().getColumnName(i));
            }
     }

I get that x is the only non-nullable column of the DB but there should be FirstColumn too.