// code/java/TestForNull.java

import java.sql.*;

public class TestForNull {
  public static void main(String[] args) {
    try (Connection conn =
            DriverManager.getConnection(
                "jdbc:mysql://localhost:3306/HW_DBPROG?user=testuser&password=password&createDatabaseIfNotExist=true&serverTimezone=UTC");
        Statement stmt = conn.createStatement(); ) {
      stmt.execute("CREATE TABLE Test (" + "A CHAR(25), " + "B INTEGER, " + "C DOUBLE)");

      String strAdd = "INSERT INTO Test VALUES (NULL, NULL, NULL);";
      int number_of_row_changed = stmt.executeUpdate(strAdd);
      System.out.print("This last query changed " + number_of_row_changed + " row(s).\n");

      ResultSet result = stmt.executeQuery("SELECT * FROM Test");

      if (result.next()) {
        System.out.print(result.getString(1) + " " + result.getDouble(2) + " " + result.getInt(3));
        if (result.getString(1) == null) {
          System.out.print("\nAnd null for CHAR in SQL is null for String in Java.\n");
        }
      }
      conn.close();
    } catch (SQLException ex) {
      ex.printStackTrace();
    }
  }
}