View source for User defined Java functions

Java classes can be stored within ASE and be used as functions accessible from T-SQL. This document shows how to enable Java in ASE, create a sample class file, store it in the database and access it through a SQL statement.
==Configuration of Java in ASE==
Enable Java in ASE with sp_configure.
 sp_configure "enable java",1
Reboot the server, it's a static setting.
==Create a Java class==
In this example a java class is created that retrieves the hostname of an (internet)server when the ip-address is supplied.
 import  java.net.InetAddress;
 import  java.net.UnknownHostException;
 
 public class HostName
 {
    public static String get(String ipaddress)
    {
        try
        {
            return  InetAddress.getByName(ipaddress).getHostName();
        }
        catch (UnknownHostException e)
        {
            return  null;
        }
    }
 }

==Compile the java file==
 javac HostName.java
==Store the class in the database==
Store the class file in a jar file. ASE can only accept jar files. When you try to store class files you will see this error:
 Server Message: ASE1 - Msg 10728, Level 16, State 1:
 The specified file or image column contains a Java class. Java classes cannot be directly installed. Enclose this class in a jar and re-try your command.

Create the jar file, it should be uncompressed.
 jar cf0 HostName.jar HostName.class
Store the jar file in the database
 installjava -f HostName.jar  -S<server> -U<username> -P<password> -D<database>
When the jar file is loaded into ASE each individual class is extracted from the jar file and stored under its own name.
==Use the java class==
Now you can use the java class:
 select HostName.get("127.0.0.1")
==Create a wrapper around the Java class==
You can create a wrapper about the java class in order to make the function more compatible with T-SQL.
 create function getHostName(ipaddress varchar(255))
 returns varchar(255)
 language java parameter style java external name "HostName.get(java.lang.String)"
Call the function like this
 select getHostName("127.0.0.1")
==Remove a java class from the database==
 remove java class HostName
==Use jdk 1.2.2==
You should compile the java source with the most old-fashioned java compiler around: version 1.2.2. When you use a more recent compiler you are able to store the jar file into the database, but at runtime you get this error:
 Msg 10707, Level 16, State 1:
 Server 'ASE1', Line 1:
 Unhandled Java Exception: 
 java.lang.ClassFormatError: HostName
Luckily you can still download this version from the archives at sun: http://java.sun.com/products/archive/j2se/1.2.2_017/index.html
This issue raises some doubts if Sybase is still really committed to this functionality. Talk to your local customer support center to get more background info on this issue.