The IBM i Java development tools help you:
Running Java applications on an IBM i server
You can import and export resources from and to the IBM i server. These resources can be data or program files. You might want to take advantage of the security available on the server, or to connect to its database. Here is a typical group of tasks you might want to perform:
Creating Java client applications
You can convert existing IBM i applications to Java client applications that access IBM i data and resources. For example, the Program Call wizard generates Java classes to call any IBM i program object or service program, such as those written in ILE RPG, ILE C, or OPM COBOL.