How the driver be loaded ?

Question

We all know using the sentences like
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
connection = DriverManager.getConnection(hostName,userName,password);
what had happended behind these two sentences ?
from the output
"DriverManager.initialize: jdbc.drivers = null
JDBC DriverManager initialized
registerDriver: driver
[className=sun.jdbc.odbc.JdbcOdbcDriver,sun.jdbc.odbc.JdbcOdbcDriver@b753f8]
The first sentence has invoked the method "DriverManager.registerDriver()"
How can the sentence do this?

Answer 1

Once the class is loaded the JDBC API makes a one or
more calls into a specific interface. That interface,
implemented as a class, registers itself with the JDBC
API.i am unsure what you mean about the JDBC API making calls into an
interface.
i think what may be confusing the original poster is that code in the
class appears to be executing when Class.forName is used to load the
class. the answer of course being that in fact that is what is happening
code is executing when the class is loaded and this has nothing to do
with JDBC per se other than what is suggested in the API that it should
do.
so for the example given the code looks something like this.
public class JdbcOdbcDriver implements Driver{
  static{
    DriverManager.registerDriver(new JdbcOdbcDriver());
     Constructors and methods go here....
}anyway i also made up a little test program to show when a static
initializer block is run.
public class Test{
  public static void main(String args[])throws Exception{
    System.out.println("Hello from Test.");
    Class c = Class.forName("StaticInit");
    System.out.println("Class is loaded.");
    Object o = c.newInstance();
    StaticInit si = (StaticInit) o;
    si.sayHello();     
class StaticInit{
  static{
    System.out.println("Hello from static initializer.");
  public void sayHello(){
    System.out.println("Hello from object method.");