★ wanayoo — archive 1999 http://www.blackdown.org/java-linux/docs/support/faq-release/FAQ-java-linux-2.htmlNouvelle recherche | Portail wanayoo
Next Previous Contents

2. About Blackdown Java for Linux

This section provides a brief overview of using the Blackdown Java platform on Linux, including an introduction to the JDK itself, a synopsis of system requirements for various editions of Blackdown Java, and how to download the bits.

2.1 Questions about the JDK

This section introduces the core Java Developer's Toolkit to Java newcomers.

Last update: 

$Id: what-is-jdk.sgml,v 1.3 2000/01/16 00:44:43 stevemw Exp $

What is Sun's JDK?

Sun's JDK , or Java Developer's Toolkit, is a complete (if Spartan) development environment supporting the Java programming language. If you're new to Java, please see section What is Java? for an introduction to the Java language.

The JDK includes the basic tools needed for developing and running Java applications, including (among other things) the following:

Note: consecutive versions of the JDK have historically included more APIs than the previous ones. See http://www.javasoft.com/products/ for more detail. Documentation for Java APIs is available separately from Javasoft at http://www.javasoft.com/docs/.

For certain Blackdown distributions, there are static and dynamic versions of the core Java binaries, as well as versions compiled with and without debugging symbols. See section Support for the Java Platform Debugging Architecture for more information about debugging Java.

For information on the Blackdown JDK porting project itself, including who the major contributors have been, please see section Who Ported the Blackdown JDK? .

Can I commercially redistribute the JDK?

According to our contacts at Sun, no. You are allowed to redistribute the JRE. See section Questions about the JRE for more information. You may also want to see section Java Licensing and the Open Source Community for the latest information about this topic. Of course, you should always contact Sun yourself if you have any questions related to your business plans.

2.2 Questions about the JRE

This section introduces the JRE, or Java Runtime Environment to Java users or developers who either need a smaller Java runtime for their applications or only want to ship the smallest JVM possible when they deploy their code as a complete application.

Last update: 

$Id: what-is-jre.sgml,v 1.3 2000/01/16 00:44:44 stevemw Exp $

What is Sun's JRE?

With Java 1.1, Sun needed a way to distribute a JVM without shipping tools for building Java classes. The JRE includes only what is required for running Java applications, including a Java Virtual Machine, the core API class libraries, and a set of default properties.

Can I commercially redistribute the JRE?

According to our contacts at Sun, yes. You may wish to contact Sun directly for case by case issues.

2.3 An Overview of Using Blackdown Java

This section provides an overview of using Java on Linux, describes the currently-supported version of the Blackdown JDK, discusses what hardware is supported, and addresses the question of whether or not Sun will support Java commercially. It's not easy to keep this section updated, so please bear with us.

Last update: 

$Id: overview.sgml,v 1.10 2000/01/24 03:45:41 stevemw Exp $

What can I expect from Blackdown Java on Linux?

You should be able to run most "pure Java" (see Sun's http://java.sun.com/100percent/ page) applications on the Linux JDK or JRE. It has tended to take longer to get the latest JDK ported to a target (Linux) that Sun didn't officially support. Javasoft and Inprise are jointly working to provide commercial support for Java on Linux now. See section Is Javasoft Going to Support Java on Linux? for more information about Sun's announcement to support Java on Linux.

For getting up and running with the Blackdown Java on your system as soon as possible, see section How do I install the JDK?.

What is the currently-supported version of Blackdown Java?

At the time of this writing, the latest supported Blackdown JDK version is 1.1.8. Both Blackdown and Inprise have "RC" (release candidate) distributions of 1.2.2 at the time of this writing.

Please see section Where do I obtain JDK 1.02, 1.1, and 1.2? for places to download.

To determine your version, use this command: 

$ java -version
Keep in mind that other Java virtual machines (JVMs) exist, so check for a README.linux file in the root directory of the distribution to ensure that it's Blackdown's.

For what other hardware architectures is Blackdown Java available?

Please see section Questions about Non-x86 Blackdown JDK Ports for more information. Also, visit the Blackdown site and check on the latest status of a given platform at http://www.blackdown.org/java-linux/ports.html.

With Java 2, it's been very difficult for Blackdown developers to keep up with the APIs and rapid development pace of Javasoft. Intel is currently the first target to get completed in any typical Blackdown development effort. More than ever before, Java 2 has showed the need for a more standardized relationship between Sun and Blackdown. We continue to ask for clarification on the developer recruiting process, code and bug exchange schedule, and for formal rules for new developer Java Compatibility Kit (JCK) access. For more on these issues, please see section Blackdown's Position on Sun's Community Source Policies.

Under what license is Blackdown Java available?

Standard disclaimer: none of this is legal advice.

Please see section How do I understand Java licensing? for more information.

Is Javasoft going to support Java on Linux?

Finally, yes. Sun is working with Inprise to outsource portions of this project. The December 7th, 1999 Inprise press-release is available at http://www.inprise.com/about/press/1999/sunlinux.html. It leads off with this statement:

Inprise Corporation (Nasdaq: INPR) today announced that it has jointly produced a Linux version of the Java(tm) 2 Platform, Standard Edition (J2SE), with Sun Microsystems. The agreement enables programmers to develop and run applications based on the Java 2 platform and deploy them on Linux workstations and servers, as well as simplify moving existing Java applications to the Linux operating system (OS).

Where can I find online reactions to the Inprise release?

In this December 9th, 1999 article http://dailynews.yahoo.com/h/zd/19991209/tc/19991209113.html by ZDnet reporter Steven J. Vaughan-Nichols, he states:

It was a press conference like any other press conference. Sun announced that, in conjunction with Inprise, it was releasing Java 2 Platform, Standard Edition (J2SE). What Sun didn't mention, though, was that much of the work that lay behind J2SE was done by the Linux Blackdown Porting Team, a group of open-source programmers devoted to Java.
An article at http://www.computerworld.com/home/news.nsf/all/9912083sunlinux by Computer World reporter by David Orenstein quotes Blackdown's Karl Asha who said,
"As the Linux community goes, I suspect they'll follow the most stable, most recent, and best-performing JDK [Java Development Kit], regardless of who produces it."
and in a December 8, 1999 press release at http://www.javasoft.com/features/1999/12/linux.html Sun acknowledges,
Blackdown has made significant advancements to the availability of Java technology for Linux," said Gina Centoni, director of product marketing for Sun Microsystems. "Sun would like to thank Blackdown for its ongoing efforts in delivering Java technology on Linux. We look forward to continued collaboration with Blackdown with the common goal of providing the Java 2 platform to the Linux community."

And in JINI-USERS posting #69 on December 8th 1999 in the thread Re: Sun releases "its" JDK for Linux - a warning for SCSL licensees, Ken Arnold said:

This matters to me, of course, because this stuff with the JDK will affect people's ideas of what we will do with the Jini technology. I can't promise no screwups, but I'm with Dick Gabriel on this one -- If I see Sun stealing credit for other people's work at this level, both my resignation and protest will be in the same letter. We will give credit where it's due. I think people who have seen us in action (for example, at the Jini Community Summits) have seen this happen.

I apologize for Sun's mistakes here, and promise that we will do our best to avoid them in the future, especially on the Jini project where we have the most control.
For more background on the Linux community's long-held hopes for full Sun support for Java, see section History of the Blackdown Java Effort.

2.4 Blackdown Java for Linux System Requirements

Discussion of hardware and software requirements for Blackdown Java.

Last update: 

$Id: requirements.sgml,v 1.2 2000/01/16 00:44:42 stevemw Exp $

What are the minimum system software requirements?

Although Blackdown developers compile and distribute Java x86 binaries compiled on RedHat 6.1, and that is considered to be the reference Linux distribution, the Linux kernel, C library, and X11R6 distribution are the essential requirements.

RedHat package name/versions are given above. More information about the GNU C library is found in section What is glibc, and Why Does it Matter?. See section Why are TrueType fonts required for Java 2? for more about TrueType.

So RedHat 6.1 is the reference Linux distribution?

Yes. This is also briefly discussed in section Is RedHat 6.1 the reference distribution for Blackdown Java?.

What are the minimum hardware requirements?

It depends on which version you run, but here are some actual numbers taken from a RedHat 6.1 x86 system. Alpha, SPARC, and PPC platforms may have different requirements.

The system used to measure these examples was a 64MB P133 running RedHat Linux 6.1 with a uniprocessor build of kernel 2.2.12-20; the above numbers were produced by the ps(1) command while running the ImageMap demo with appletviewer.

If you have the memory requirements suggested above, and you still have fatal errors related to running out of memory, see section Help, Java Said it Ran out of Memory! for suggestions of flags to pass to the JVM for setting memory and stack allocation limits. Java uses a lot of memory, so be prepared to specify additional RAM in your application deployment recommendations.

What about my particular hardware platform?

See section Questions about x86 Blackdown Java Ports for information about x86 platforms (including Intel and clone builds). See section Questions about Non-x86 Blackdown Java Ports for other targets.

2.5 Downloading Blackdown Java for Linux

Help with downloading Blackdown Java.

Last update: 

$Id: download.sgml,v 1.9 2000/01/15 21:52:19 stevemw Exp $

Where do I obtain JDK 1.02, 1.1, and 1.2?

Please visit http://www.blackdown.org/java-linux/mirrors.html and select the site nearest you. Both Randy Chapman's JDK 1.02 and Steve Byrne's JDK 1.1.x are found on participating mirror sites. Check section What is the currently-supported version of Blackdown Java? for the currently supported version the Blackdown JDK.

How do I install?

See section How do I install the JDK?.

What is the currently-supported version of Blackdown Java?

Which is the latest version?

For the latest status on a given JVM, check the Java-Linux Ports page at http://www.blackdown.org/java-linux/ports.html

OK, which version of the JDK should I download?

This section describes the organization of the Blackdown distribution mirror hierarchy. You may also be interested in reading section What System Configuration do I Need to Run the JDK? before you decide what to download.

After reading this, if you're still wondering which individual archive to download, please see What are These Files? below.

JDK 1.02 Downloads:

This version of the Blackdown JDK is only supported on Intel. If you know of other Linux platforms to which the JDK has been ported, please tell the FAQ maintainer. Look for the mirror closest to you by following instructions in section Where to obtain JDK 1.02, 1.1, and 1.2?.

JDK 1.1 Downloads:

JDK 1.1.7 was the latest release to compile on all platforms. You may need to visit http://www.linuxppc.org/java/ in order to obtain the PPC version. Intel and ARM have support in 1.1.8. For the latest on Java 1.1, see section Information relevant to the Blackdown 1.1 JDK.

Here's a view of the 1.1.7 directory:

You may wish to read section What is glibc, and Why Does it Matter? to help you understand which Intel JDK to download.

For an official description of the FTP site, look for an up to date version of http://www.blackdown.org/java-linux/docs/faq/README/FTP, at the top level of your closest mirror.

To just run the JDK, you don't need anything out of common/. Those diff(1) files are for people who want to request free access to the SPARC/x86 Solaris and i386 Win32 sources from Sun and help with the port. See section Compiling the Blackdown JDK from Source for more information.

What are these files in the FTP mirror directories?

By now, many readers are still wondering what each archive in the mirror directories is. Below is a representation of what your favorite web browser would have displayed if you were visiting a Blackdown JDK mirror recently. 

Current directory is
/pub/linux/devel/lang/java/blackdown.org/JDK-1.1.7/i386/glibc/v3
    README.linux
    i18n_1.1.7-v3-glibc-x86.tar.bz2
    i18n_1.1.7-v3-glibc-x86.tar.gz
    jdk_1.1.7-v3-glibc-x86-native.tar.bz2
    jdk_1.1.7-v3-glibc-x86-native.tar.gz
    jdk_1.1.7-v3-glibc-x86.tar.bz2
    jdk_1.1.7-v3-glibc-x86.tar.gz
    jre_1.1.7-v3-glibc-x86-native.tar.bz2
    jre_1.1.7-v3-glibc-x86-native.tar.gz
    jre_1.1.7-v3-glibc-x86.tar.bz2
    jre_1.1.7-v3-glibc-x86.tar.gz
    rt_1.1.7-v3-glibc-x86-native.tar.bz2
    rt_1.1.7-v3-glibc-x86-native.tar.gz
    rt_1.1.7-v3-glibc-x86.tar.bz2
    rt_1.1.7-v3-glibc-x86.tar.gz
As a hypothetical user, you've already decided that your system is based on glibc (perhaps by reading What is glibc, and Why Does it Matter?). Now you'd like to know what these four files do for you, and which ones you should download.
  1. jdk. The JDK contains everything you need to run Java, compile Java, and debug java. It doesn't contain the international character converters (see i18n).
  2. jre. The JRE is the Java runtime environment, including the international character converters.
  3. rt. The Java RT is the minimal configuration you can have to run Java. It doesn't contain any internationalization support.
  4. i18n. This contains font mappings and a JAR file containing the international character converters, and really doesn't need to be split off by library type, but is anyway.
  5. *native*. These are additional binaries that provide support for native threads (according to command-line options and environment variables).
For more about Blackdown Java 1.1, see section Information relevant to the Blackdown 1.1 JDK., although most 1.1 information is distributed throughout the FAQ.

When do I need extra *native* binaries?

All versions of Blackdown Java up through 1.1.7v3 required you to take the extra step of installing a package of shared libraries containing native the threads VM if you wanted to effectively run with the -native flag. Blackdown Java 1.1.8 does not require you to unpack anything special. See the section Is there a native threads port of Blackdown Java? for a little more information.

JDK 1.2 Downloads:

At this time, only the sparclinux and i386 directories were populated. Internationalization is included, as well as native threads support. For more about Blackdown Java 2, see section Information relevant to the Blackdown 2.x Java Ports.

How should I download Java archives ending in .sh?

These are files that consist of a shell-script at the top and a ZIP file containing the binary archive of the Java product you wish to download. Please use binary mode.

How do I deal with downloaded files ending in .bz2?

These are bzip2 compression arcvhies. Please see The bzip2 and libbzip2 Official Home Page at http://sourceware.cygnus.com/bzip2/ for availability of precompiled bunzip2(1) executables (as well as source code). However, you should have this on any contemporary distribution of Linux.

Hey, why doesn't Blackdown use xdelta?

Several of you have requested that we supply XDELTA binary patches in order to save download time. At the time of this writing, no one had time to consider doing this extra step. However, we're looking for volunteers to help with development, and if you were willing to work on this sort of thing, it would be helpful.

For more information about XDELTA (it is cool), feel free to visit http://www.xcf.berkeley.edu/~jmacd/xdelta.html.

Next Previous Contents