Can Java run on the Mainframe instead of Cobol?

C/C++ and Java for MVS & zOS.
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Raghav
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Can Java run on the Mainframe instead of Cobol?

Post by Raghav »

Hi,

Can Java run on the Mainframe instead of Cobol? My question can be misleading as I've some knowledge about JAVA on mainframes. But very curious to know if Java will ever replace COBOL on the mainframe? Most of my generation, of mid 20s, has either never used COBOL or taken like one class in college on it.
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Robert Sample
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Re: Can Java run on the Mainframe instead of Cobol?

Post by Robert Sample »

But very curious to know if Java will ever replace COBOL on the mainframe?
Could JAVA replace COBOL? Certainly. Will JAVA replace COBOL? The economics are not favorable. Suppose a company has 1,000,000 lines of COBOL code, and further suppose JAVA code can replace COBOL code 1-for-1. So the company needs 1 million lines of JAVA to replace their existing COBOL code base. The last estimate I have indicates a programmer can write about 5 debugged, tested lines of code per hour. So the company has a project requiring 200,000 hours of effort to convert the COBOL to JAVA. The company gets executive approval, hires contractors, and spends a year (or two or three) converting their COBOL code to JAVA. At the end of that effort, and after spending a lot of money for resources, what the company has is exactly what they are running today, just in JAVA instead of COBOL. In the meantime, their competitors spent that year (or two or three) writing new applications to take market share. The reality is that the IT managers in the company wouldn't consider such an idea, and the executives would not approve the resources for such a project. So any conversion of COBOL to JAVA is going to be slow as existing applications are upgraded (we're talking probably a decade or two, or more). A million lines of COBOL could be as little as a couple hundred programs, and most sites using COBOL have thousands of programs, not a few hundred -- so the actual numbers could be much higher than my example.
Most of my generation, of mid 20s, has either never used COBOL or taken like one class in college on it.
Colleges market themselves to attract students. And students like new, shiny, glittery things. Most colleges require certain classes be taken to ensure the student education is more rounded than if they self-selected classes. Students are attracted to JAVA (Ruby, PHP, you name the latest fad language) over COBOL, so colleges teach JAVA instead of COBOL (Ruby, PHP, you name the latest fad language). The reality of the marketplace is that a lot of COBOL programmers are getting to retirement age and companies are EXTREMELY concerned about being able to replace them. And if a conversion effort occurs, somebody has to be able to read the COBOL code, extract the business rules / processes involved in the code, and work with the JAVA programmers to translate the business rules / processes.
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Anuj Dhawan
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Re: Can Java run on the Mainframe instead of Cobol?

Post by Anuj Dhawan »

The last estimate I have indicates a programmer can write about 5 debugged, tested lines of code per hour.
This statistics miss to include the "Software Engineer" factor, no!? :mrgreen:

Excellent post - Robert!
Thanks,
Anuj

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Robert Sample
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Re: Can Java run on the Mainframe instead of Cobol?

Post by Robert Sample »

My personal observation, based on more than 38 years of work experience in applications development, software sales and support, and systems programming, is that 5 to 10 lines of code per hour are probably average. A really good programmer might be able to hit 50 lines per hour for short periods of time. But then the team meetings, design reviews, code walkthroughs, testing design, test outcome reviews, and all the other meetings start filling up the calendar .....

And even allowing 50 lines of code per hour doesn't really change the economics of conversion a whole lot -- it just isn't worth it for a company to invest in changing from one language to another when the current code is meeting the need. Upgrading code over time can make sense, but there's a lot of business logic built into current programs and sometimes it isn't easy for that business logic to be captured in a new language.

And thanks for the kind words, Anuj!
Raghav
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Re: Can Java run on the Mainframe instead of Cobol?

Post by Raghav »

Thanks Robert and Anuj... those statistics make me believe that it would be a big task to convert all that code but even though the jobs in to mainframes does not come with good pay check. While the statement like this can be trure:
Colleges market themselves to attract students. And students like new, shiny, glittery things. Most colleges require certain classes be taken to ensure the student education is more rounded than if they self-selected classes. Students are attracted to JAVA (Ruby, PHP, you name the latest fad language) over COBOL, so colleges teach JAVA instead of COBOL (Ruby, PHP, you name the latest fad language).
is not that true?
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