[Techtalk] Java on Linux

Xp0nential Xp0nential Xp0nential at root-core.com
Thu Jan 10 14:02:50 EST 2002

from the top of my head:
the reasons why Java is slow:
* Runtime binding
* Lazy Class loading and linking
* Garbage Collection
* Languagel-level multithreading
*Very slow expection handling

--- Aaron Mulder <ammulder at alumni.princeton.edu> wrote:
>On Thu, 10 Jan 2002, Xp0nential Xp0nential wrote:
>> I don't paricularly like Java that much. One of the reasons being the
>> VM required to run Java Apps is memory consuming, thus most Java
>> Programs are comparably slow.
>	I don't understand.  How does using more memory make a program 
>slower?  Only if you start swapping, but most systems have at least 20 or 
>30 MB of free memory...
>> It would be cool if this feature gets enhanced.  But still I am more
>> into system/low level programming. SO I'll stick to my C/assembly
>> knowledge :)
>> Regards,
>> Xp0nential
>> --- Aaron Mulder <ammulder at alumni.princeton.edu> wrote:
>> >	Well, I can't speak for FreeBSD, but I do Java development on
>> >Linux for work, so I can at least help get up and running there.  
>> >(According to Google, a FreeBSD JDK is available via "ports", and a native
>> >JDK may be included in the forthcoming FreeBSD 4.5)
>> >
>> >	First, there's a 3-tier Java process on Linux.  Sun has a JDK,
>> >which they have adapted for Linux.  Then Blackdown (blackdown.org) tweaks
>> >Sun's release to work a little better on Linux (and support more CPU types
>> >than x86), and then Caldera tweaks Blackdown's release to work a little
>> >better on their distro.
>> >	As well, IBM has released a JDK for Linux, which is well-regarded.  
>> >I think it may be based on the Sun source code, but it has diverged 
>> >greatly, including using a non-HotSpot VM.
>> >	If you're new to Java on Linux, I'd try Blackdown's JDK first.  
>> >In the Sun or Blackdown case, you're probably safest going with 1.3.1 for
>> >now -- IBM just calls theirs "1.3", though they're up to "Service Release 
>> >10" now.
>> >
>> >	Whichever you pick, you should download a .tar.gz package instead
>> >of an RPM -- this ensures that everything will be installed under one
>> >directory, and you can more conveniently pick that directory.  
>> >Personally, I use /usr/local/java as the root of all my Java
>> >installations, but it matters little.  So go to your favorite directory 
>> >and tar -xzf and you should get "jdk1.3.1/" or "j2sdk1.3.1/" or 
>> >"IBMJava2-13/" or whatever.
>> >	To see whether it works, go to the JDK directory and run
>> >"bin/java -version".  You should get something like:
>> >
>> >java version "1.3.1"
>> >Java(TM) 2 Runtime Environment, Standard Edition (build Blackdown-1.3.1-FCS)
>> >Java HotSpot(TM) Client VM (build Blackdown-1.3.1-FCS, mixed mode)
>> >
>> >	If it craps out, let me know the error message.  With the original 
>> >1.3.0 series, there was a problem using certain Linux kernels that could 
>> >be resolved by adding some env variable in the Java startup script to 
>> >claim you were running 2.2.5 -- we can look that up.
>> >	If you get a bunch of font not found messages when you run a GUI 
>> >application, there's an updated "jre/lib/font.properties" that Sun links 
>> >to in their release notes for 1.3.1.  This has been a problem on Red Hat 
>> >7.x for me, but it's easy to fix.
>> >
>> >	Anyway, if "java -version" runs successfully, then you can either 
>> >add <jdk>/bin to the system path (in /etc/profile) or create a little 
>> >script to set the path and JAVA_HOME for your current shell.  I prefer the 
>> >latter on a development box, since it's easier to swap between JDKs, but 
>> >otherwise there's no reason not to set it for the whole system.
>> >
>> >	Beyond the JDK, I use JBuilder 4/5 for development, as well as a
>> >boatload of open-source projects, and I can help get those configured too.
>> >
>> >Aaron
>> >
>> >ftp://metalab.unc.edu/pub/linux/devel/lang/java/blackdown.org/JDK-1.3.1/i386/FCS/j2sdk-1.3.1-FCS-linux-i386.tar.bz2
>> >http://java.sun.com/j2se/1.3/download-linux.html
>> >http://www6.software.ibm.com/dl/dklx130/dklx130-d?S_PKG=devkit&S_CMP=&S_TACT=
>> >
>> >On Thu, 10 Jan 2002, Amanda Babcock wrote:
>> >> > I'd be interested in that, especially from a Linux perspective.
>> >> > I've written some applets, and periodically think about updating
>> >> > my Java knowledge to get more fluent in new stuff like J2EE/Swing,
>> >> > but I keep hitting problems getting downloaded JDKs to work at all,
>> >> > and all the Java folks I know are Windows users.  
>> >> 
>> >> Ooh, yeah!  I've tried to learn Java before only to find that I couldn't
>> >> figure out the basic "install what where, invoke it how" questions and
>> >> quit in frustration.
>> >> 
>> >> Of course, there's the fact that I'm actually on FreeBSD, not Linux...
>> >> which means a certain amount of translating in the "where" department :)
>> >
>> >
>> >
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