"the JVM has excellent support for production logging and production monitoring, allowing you to easily monitor performance metrics down to an individual thread" Is it "excellent" compared to z/OS and mainframe (SMF and RMF, specifically)? I sincerely doubt it, but I would like to know if there is someone who can compare. I don't think any platform can match z/OS in the visibility into the system, but I am not enough…
You're comparing an OS independent language to an entire operating system? I think you're probably right, I don't think there is a sane comparison. But I don't think that's what the parent was referring to. I'm not sure there are too many languages that provide (eg via slf4j or JMX) extremely customisable, universal logging and monitoring across multiple libraries that are used together in a single application. That'…
No, I am not comparing Java, but JVM. JVM is a platform, so it should have insight what's happening on it, don't you think? Whether this insight comes from the platform (JVM or z/OS) or the underlying system (native host OS or mainframe) is irrelevant - you probably want both (and in z/OS you get both).
Whether Java (the language) is clunky is irrelevant - z/OS has lot clunkier languages on it (application development is huge pain on z/OS compared to JVM), and I still think z/OS beats JVM for large/complex/maintainable systems. ;-) (Basically for the same reason - more mature.) z/OS has many logging and tracing functions, at different granularity, some of them are assisted with mainframe hardware. I don't see how JVM could beat it, but I may be wrong.