Dynamic Class Loading

SQL Anywhere and Adaptive Server allow you to specify Java classes.

Datatypes of SQL columns
Datatypes of Transact-SQL variables
Default values for SQL columns

jConnect version 6.05 and later implements DynamicClassLoader (DCL) to load a class directly from an SQL Anywhere or Adaptive Server server and use it as if it were present in the local CLASSPATH.

In jConnect 6.0 and earlier versions, only classes that appeared in the jConnect CLASSPATH were accessible, that is, any attempt of a jConnect application to access an instance of a class that was not in the local CLASSPATH, resulted in a java.lang.ClassNotFound exception.

All security features present in the superclass are inherited. The loader delegation model implemented in Java 2 is followed—first jConnect attempts to load a requested class from the CLASSPATH; if that fails, jConnect tries the DynamicClassLoader.

See Java in Adaptive Server for more detailed information about using Java and Adaptive Server.

Using DynamicClassLoader
Use the CLASS_LOADER connection property to provide a convenient mechanism for sharing one class loader among several connections.
Deserialization
The serialized object is an instance of a class that resides on a server and does not exist in the CLASSPATH.
Preloading .jar Files
jConnect version 6.05 or later has a connection property called PRELOAD_JARS. When defined as a comma-delimited list of .jar file names, the .jar files are loaded in their entirety.
Additional Dynamic Class Loading Features
Additional features include the ability to keep the database connection of a loader alive when a series of class loads is expected, and to explicitly load a single class by name.

Parent topic: Advanced Features in jConnect