Java on z/OS
Running Java programs on z/OS, in batch, in CICS and in application servers, next to traditional mainframe programs.
Also written IBM Semeru, Java batch, JZOS, Liberty
Java is widely used on z/OS. IBM provides its own Java runtime for z/OS, and Java programs run in Unix System Services, in batch jobs, inside CICS, in IMS, in DB2 stored procedures and in application servers such as Liberty.
One reason it is popular on the mainframe is cost. Java work can run on zIIP processors, which are priced differently from general purpose processors. Another is people: it is much easier to hire Java developers than COBOL developers, and Java brings many libraries for things like web services, JSON and security.
Java on z/OS can work with traditional mainframe data. JZOS, part of IBM's Java for z/OS, lets Java programs read and write datasets and run as normal batch job steps. Java and COBOL can call each other, for example inside CICS, so a site can add new Java code to an existing COBOL application.
For a developer, Java on z/OS is mostly the same Java you know. The differences are in how it is started, how it reaches datasets, and the EBCDIC character set of the data around it.
Where can I learn this hands-on?
Right here, at ZedBank. You take a junior job at a simulated bank and learn each part of the work by doing it, with Zed beside you. There's nothing to install.
Start at ZedBankRelated
- Unix System ServicesA full Unix environment built into z/OS, with a shell, directories and files alongside the traditional mainframe world.
- Specialty engineA mainframe processor set aside for one kind of work, such as Linux or certain z/OS workloads, and usually priced lower than a general processor.
- CICSThe transaction manager that runs online mainframe applications, and the software behind a great many screens bank staff use.
- Stored procedureA program stored in DB2 and run with a single SQL CALL, so an application can do several database steps in one request.
- z/OS ConnectIBM software that makes mainframe programs and data available as REST APIs, so web and mobile applications can use them.