JVM vs .NET

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Jon Harrop - 06 Oct 2007 06:37 GMT

I'm relatively new to both the JVM and .NET and am learning Scala and F#. I
was under the impression that .NET was essentially a later and greater
reimplementation of the JVM in a Windows-specific form. However, I've just
discovered some nasty caveats in .NET.

Specifically, if you generate and use regular expressions the obvious way
then .NET leaks memory because it performs run-time compilation to improve
performance but fails to garbage collect the generated code when it is no
longer needed. There are workarounds but I've yet to see a solution that
can even garbage collect code under .NET properly, let alone an elegant
solution.

So I'm wondering what the JVM crowd have to say about the relative
deficiencies of the JVM and .NET. Does the JVM garbage collect code
correctly? Are there glaring flaws in the JVM?

I'm aware of the array covariance problem in the JVM.

Signature

Dr Jon D Harrop, Flying Frog Consultancy
http://www.ffconsultancy.com/products/?u

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EricF - 07 Oct 2007 05:34 GMT

>I'm relatively new to both the JVM and .NET and am learning Scala and F#. I
>was under the impression that .NET was essentially a later and greater
[quoted text clipped - 13 lines]
>
>I'm aware of the array covariance problem in the JVM.

The JVM does a good job of garbage collecting, though 1 can write code with
memory leaks. At my previous company, our Java app servers ran 24 by 7 for 3
months bewfore being bounced, and that was because we relased new applications
quarterly. This was on Solaris.

There is a 2 gig memory limit on Windows for a Java process. This is a Windows
constraint.

Eric

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Roedy Green - 11 Oct 2007 02:19 GMT

> can write code with
>memory leaks.

do you mean leaks or packratting?

See http://mindprod.com/jgloss/packratting.html

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Roedy Green Canadian Mind Products
The Java Glossary
http://mindprod.com

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Roedy Green - 11 Oct 2007 02:18 GMT

>So I'm wondering what the JVM crowd have to say about the relative
>deficiencies of the JVM and .NET. Does the JVM garbage collect code
>correctly? Are there glaring flaws in the JVM?

.net's main problem is it single source. You are trusting a company
with a bad record of betraying trust.

.net's big advantage is you can also do low level unsafe code in it.
With the JVM you must revert to C++ and native code.

.net is designed for compilation. Java is designed for interpreting
and hotspotting. Java allows elaborate dynamic run time tricks.

Both are in theory multiplatform, but JVMs have been much more widely
implemented.

.net was designed to support a wide variety of languages. Java was
designed specifically for Java, though it supports many others too.

Signature

Roedy Green Canadian Mind Products
The Java Glossary
http://mindprod.com

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Gordon Beaton - 11 Oct 2007 17:34 GMT

> Both are in theory multiplatform, but JVMs have been much more widely
> implemented.

Mono, an open source implementation of .NET, runs on more platforms
than Java judging from the long list of OS and HW platforms they list.

http://www.mono-project.com

/gordon

--

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Nikolaus Wagner - 12 Oct 2007 22:41 GMT

>> Both are in theory multiplatform, but JVMs have been much more widely
>> implemented.
[quoted text clipped - 3 lines]
>
> http://www.mono-project.com

Well, it would be fine if Mono ran anything with a GUI :-(
(Well, a Windows.Forms GUI, not Gtk# or whatever)
Paint.net or Sharpdevelop running on Mono would be nice, but may never
be.

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JVM vs .NET

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