🚀 go-pugleaf

George wrote:

>       URLClassLoader cld = new URLClassLoader(urlList);
>       Class cl = cld.loadClass("oracle.jdbc.OracleDriver");
>       Connection connection = DriverManager.getConnection("jdbc:oracle:thin:@STPDB1P:1521:STP20P1", "fo", "fo");

This is really unlikely to work. Even if you had created "cld" with its 
parent set to ThisClass.getClass().getClassLoader(), you'd still have 
this hierarchy:

     ThisClass  <-     loaded by base class loader

     OracleDriver <-   loaded by "cld" (assuming that ojdbc14.jar is not 
in your regular classpath)

Remember that each class is loaded *in its own classloader* only. It is 
not visible to classes loaded by its parent classloader, or by classes 
loaded by other classloaders unrelated to its classloader.

So, OracleDriver in the above example is only visible to classes loaded 
by "cld", or by other classloaders that are children of "cld".

There's more to what Cayenne is doing than just making cld's parent the 
calling class' classloader. Check carefully to see how they make the 
driver visible.

I strongly suspect that they are doing something like this:

     URLClassLoader cld = new URLClassLoader(urlList);
     Class driverClass = cld.loadClass("oracle.jdbc.OracleDriver");
     // call the default constructor of the driver class
     // using reflection:
     Object driverObj = driverClass.newInstance();

At this point, assuming that oracle.jdbc.OracleDriver has a default 
constructor (should have), you'll see that the driver is now registered, 
and DriverManager.getConnection() should now work.

PS. Check the documentation to see if the preferred class is 
oracle.jdbc.OracleDriver, or oracle.jdbc.driver.OracleDriver. My memory 
is that Oracle now prefers that you use the latter name..