You can install the AS/400 Toolbox for Java classes on your workstation or on the AS/400:
Important performance tip regarding the CRTJVAPGM command:
If your Java program runs on the AS/400 Java Virtual Machine (JVM), you can significantly improve performance if you create an AS/400 Java program from the AS/400 Toolbox for Java zip file or jar file. Enter CRTJVAPGM on an AS/400 command line to create the program. You must run the CRTJVAPGM command at Level 30 to ensure proper protection of your program resources. (See the online help information for the CRTJVAPGM command for more information.) By using the CRTJVAPGM command, you save the AS/400 Java program that is created (and that contains the AS/400 Toolbox for Java classes) when your Java program starts. Saving the AS/400 Java program that is created allows you to save startup processing time. You save startup processing time because the AS/400 Java program does not have to be re-created each time your Java program is started.
If you are using the V4R2 or V4R3 version of the AS/400 Toolbox for Java, you cannot run the CRTJVAPGM command against the jt400.zip file because it is too big. At V4R4, the AS/400 Toolbox for Java licensed program includes an additional file, jt400access.zip. jt400access.zip contains only the access classes, not the visual classes. If your Java program will be running on the AS/400, you should use jt400access.zip because you probably only need the access classes. The CRTJVAPGM command has already been run against jt400access.zip.