4 ms·

I love all those 'JVM roks!' or 'JVM is mature and stable!' stories. But I still unable to get it, why one user-level program (say, java.exe) must be better tha

I love all those 'JVM roks!' or 'JVM is mature and stable!' stories. But I still unable to get it, why one user-level program (say, java.exe) must be better than any another user-level .exe? With its primitive and rudimentary integration with an OS (remember, it was designed to be isolated environment that runs everywhere, which means exactly opposition to efficiency and optimization). Wait! It can produce native code and able to run threads! Yeah, but LLVM produces much better code and there is clang++ with which we can build java.exe from its sources... ^_^ May be it rocks just because too much money was invested in the ecosystem and now they do everything possible to keep it breathing? ^_^ Remember? Your lovely Xeon CPU is a VM itself. Your lovely Virtualization stack on top of your OS is what? Do we still need so many layers of VMs? ^_^ btw, MS DOS is also quite mature, stable and production ready environment. Especially with something like qemm.exe and desqview.exe (do you remember them?)

antrix 15y ago
A best of breed garbage collector is a strong argument for the JVM.
- deleted 15y ago
  [deleted]
teyc 15y ago
If I remember Cliff Click's [Azul] lecture "A JVM does what?" correctly, each machine whether JVM or x86 defines what is managed by the machine and what isn't. Just as x86 represents a machine which defines op codes only and leaves memory and process management to the operating system, the outcome of JVM's choices about taking responsibility for garbage collection, security, machine code generation is an interesting machine which can provide performance gains through time, just like Moore's law. I don't work with the JVM at all, so all I know I learnt from Cliff's lecture. The slides are here http://www.azulsystems.com/blog/wp-content/uploads/2011/03/2011_WhatDoesJVMDo.pdf http://www.azulsystems.com/blog/wp-content/uploads/2011/03/2... and video here: http://jeremymanson.blogspot.com/2011/04/cliff-click-in-jvm-does-what.html http://jeremymanson.blogspot.com/2011/04/cliff-click-in-jvm-...
rat 15y ago
I'm not sure I understand what does compiling a javam have to do with replacing a vm with a compiler? The jvm has really good garbage control and a good jit compiler. LLVM has some of the stuff needed for writing a jit compiler for a vm. I'm not sure whether a compiler for a garbage collected language will be faster then a jit compiler.

antrix 15y ago

A best of breed garbage collector is a strong argument for the JVM.

deleted 15y ago
[deleted]

teyc 15y ago

If I remember Cliff Click's [Azul] lecture "A JVM does what?" correctly, each machine whether JVM or x86 defines what is managed by the machine and what isn't. Just as x86 represents a machine which defines op codes only and leaves memory and process management to the operating system, the outcome of JVM's choices about taking responsibility for garbage collection, security, machine code generation is an interesting machine which can provide performance gains through time, just like Moore's law. I don't work with the JVM at all, so all I know I learnt from Cliff's lecture. The slides are here http://www.azulsystems.com/blog/wp-content/uploads/2011/03/2011_WhatDoesJVMDo.pdf http://www.azulsystems.com/blog/wp-content/uploads/2011/03/2... and video here: http://jeremymanson.blogspot.com/2011/04/cliff-click-in-jvm-does-what.html http://jeremymanson.blogspot.com/2011/04/cliff-click-in-jvm-...

rat 15y ago

I'm not sure I understand what does compiling a javam have to do with replacing a vm with a compiler? The jvm has really good garbage control and a good jit compiler. LLVM has some of the stuff needed for writing a jit compiler for a vm. I'm not sure whether a compiler for a garbage collected language will be faster then a jit compiler.