JDBC- Implementation of interfaces

by

In JDBC you first register a driver by calling

Class.forName('classname')

which loads the Database class and registers that class with DriverManager

When you say DriverManager.getConnection() – It returns you java.sql.Connection (the contract as per specification)

Which class implements these methods?

The actual implementation is provided by the database vendor, for e.g. Oracle, MySQL.

Why it is called as connection object instead of implemented class
object?

Because you code to Interface and not implementation (good coding practice).

If you want you can look up in the vendor jar and find which class implements Connection then instead of 

Connection connection = DriverManager.getConnection()

you can write 

VendorConnectionImpl vendorConnection = (VendorConnectionImpl)DriverManager.getConnection()

This above will work but then it will bind you with that specific implementation.

If you want to move from vendor1 to vendor2 you cannot do that, first you will have to change the above code as per vendor2 API, But if you use the first approach you can move from Vendor to Vendor without having pain of changing your code.

More Related Contents:

  1. SQL syntax error in "insert into 'keys'(a,b,c,d,e) values(?,?,?,?,?)" [closed]
  2. Hours and seconds are lost when storing a date in the database [closed]
  3. Connection pooling options with JDBC: DBCP vs C3P0 [closed]
  4. Find Oracle JDBC driver in Maven repository
  5. ClassNotFoundException com.mysql.jdbc.Driver [duplicate]
  6. Efficient way to do batch INSERTS with JDBC
  7. Java: Insert multiple rows into MySQL with PreparedStatement
  8. Named parameters in JDBC [duplicate]
  9. What is the actual use of Class.forName(“oracle.jdbc.driver.OracleDriver”) while connecting to a database?
  10. No suitable driver found for ‘jdbc:mysql://localhost:3306/mysql [duplicate]
  11. com.mysql.jdbc.exceptions.jdbc4.CommunicationsException:Communications link failure [duplicate]
  12. When to close Connection, Statement, PreparedStatement and ResultSet in JDBC
  13. java.sql.SQLException: Exhausted Resultset
  14. java.util.stream with ResultSet
  15. How to get a value from the last inserted row? [duplicate]
  16. handling DATETIME values 0000-00-00 00:00:00 in JDBC
  17. JDBC ResultSet get columns with table alias
  18. How to start a transaction in JDBC?
  19. Getting an exception ORA-00942: table or view does not exist – when inserting into an existing table
  20. Driver JDBC PostgreSQL with Android [duplicate]
  21. ‘0000-00-00 00:00:00’ can not be represented as java.sql.Timestamp error
  22. oracle.jdbc.driver.OracleDriver ClassNotFoundException
  23. Populating jTable using database data
  24. SQL Error: 0, SQLState: 08S01 Communications link failure [duplicate]
  25. How to correctly write UTF-8 strings into MySQL through JDBC interface
  26. How to get the number of columns from a JDBC ResultSet?
  27. Resultset To List
  28. How do you enforce foreign key constraints in SQLite through Java?
  29. Performance of MySQL Insert statements in Java: Batch mode prepared statements vs single insert with multiple values
  30. Iterating a ResultSet using the JDBC for Oracle takes a lot of time about 16s?

Leave a Comment