IBM(R) Runtime Environment for Linux(R), Java(TM) 2 Technology Edition, Version 1.3.0 README


(c) Copyright IBM Corporation 1999, 2001. All rights reserved.

(c) Copyright Sun Microsystems, Inc. 1997, 2001. 901 San Antonio Rd., Palo Alto, CA 94303 USA. All rights reserved.

Note: The complete copyright citation is included in the Notices section of this document.


This README file provides information about the Runtime Environment for Linux package provided with IBM Developer Kit for Linux, Java 2 Technology Edition, Version 1.3.0.

For the list of distributions against which the Developer Kit for Linux has been tested, see:
http://www-106.ibm.com/developerworks/java/jdk/linux/tested.html


Contents

  • Overview
  • Files included with the Runtime Environment for Linux
  • License agreement
  • The just-in-time (JIT) compiler
  • Java programs, the Native Method Interface, and the Java Native Interface
  • Configuring the Runtime Environment for Linux
  • Installing and configuring the Java Plug-ins for Netscape 4.x and Netscape 6
  • Installing additional fonts
  • Updating the glibc on Caldera eServer 2.3
  • Uninstalling the Runtime Environment for Linux
  • Uninstalling the RPM package
  • Uninstalling the compressed TAR package
  • Invoking the Java Runtime Interpreter
  • System properties
  • Obtaining the IBM build and version number
  • Euro symbol support
  • Unicode support
  • Collation of currency symbols
  • Switching the input method in DBCS languages
  • Runtime example
  • Installing your application on a user's system
  • Runtime Environment for Linux documentation
  • Known limitations
  • Information for Japanese users
  • Notices
  • Trademarks

  • Overview

    The Runtime Environment for Linux contains the subset of classes required to create a Java runtime environment and to run Java programs. It also contains the Java Virtual Machine, Java classes, and supporting files. The Runtime Environment for Linux contains only a subset of the classes found in the Java Developer Kit.


    Files included with the Runtime Environment for Linux

    The Runtime Environment for Linux includes non-debuggable .so files plus class files needed to support a program at runtime. The Runtime Environment for Linux does not include any of the development tools, such as appletviewer or javac, or classes that would pertain only to a development system.

    In addition, the Java Authentication and Authorization Service (JAAS) and Java Communications application programming interface (API) packages are provided for use with the Runtime Environment for Linux.


    License agreement

    The LICENSE_xx.html file contains the license agreement for the Runtime Environment for Linux software. (xx is an abbreviation for the language.)

    To view or print the license agreement, open the file in a Web browser.


    The just-in-time (JIT) compiler

    The just-in-time (JIT) compiler (libjitc.so) dynamically generates machine code for frequently used bytecode sequences in a Java application or applet while it is running.

    The Runtime Environment for Linux includes the JIT compiler (libjitc.so), which is enabled by default. You can disable the JIT to help isolate a problem with a Java application, an applet, or the compiler itself. To disable the JIT, type the following at a shell prompt:

        export JAVA_COMPILER=NONE
    

    To enable the JIT, type the following at a shell prompt:

        export JAVA_COMPILER=jitc
    

    To verify whether or not the JIT is enabled, type the following at a shell prompt:

        java -version
    

    If the JIT is in use, a message is displayed that includes the following:

        JIT enabled: jitc
    

    If the JIT is not in use, the following message is displayed:

        JIT disabled
    

    Java programs, the Native Method Interface, and the Java Native Interface

    IBM does not support the Native Method Interface in this release. Do not use this interface in your applications.

    The Java Native Interface (JNI) is included with the Runtime Environment. For information about using the JNI, see the following Sun Web site:


    Configuring the Runtime Environment for Linux

    After you install the Runtime Environment for Linux, edit your shell script and add to your PATH statement the following directories:

    If you installed the Runtime Environment for Linux in a directory other than /opt/IBMJava2-13, replace /opt/IBMJava2-13 with the directory in which you installed the Runtime Environment for Linux.


    Installing and configuring the Java Plug-ins for Netscape 4.x and Netscape 6

    To install and configure the Java Plug-in for Netscape 4.x:

    Notes:

    To install and configure the Java Plug-in for Netscape 6:

    Notes:

    To configure the Java Plug-in:

    You can change the configuration of the Java Plug-in by using the control panel, which runs as a standalone Java application. To launch this Java application, run the JavaPluginControlPanel shell script, which is located by default in /opt/IBMJava2-13/jre/bin. The results of this Java application are stored on a per-user basis in ~/.java/properties. The control panel application allows you to change several properties of the Java Plug-in, such as whether or not the Java Console is displayed when the applet is invoked.


    Installing additional fonts

    Java is able to display all Unicode characters, but most versions of Linux install only the fonts needed to show your language. You can download fonts from IBM that allow you to see the complete Unicode character set. These fonts are not included in the Runtime Environment for Linux package because they are large and not all users need them. IBM supplies two Unicode fonts, and each of them is customized by country. Users in China and Korea should use the country specific versions, and all others should use the Japanese version of these fonts.

    If you did not download fonts, you can get them from the DeveloperWorks Web site at http://www.ibm.com/developer/java/ where you download the IBM Developer Kit for Linux, Java 2 Technology Edition, Version 1.3.0. Descriptions of the fonts are provided to help you decide which fonts to download.

    To install a font, put the file in the /opt/IBMJava2-13/jre/lib/fonts directory.

    If you download fonts in parts, you must first put the fonts back together into one file for each font.

    To put a font file back together, be sure the file is in the /opt/IBMJava2-13/jre/lib/fonts directory and use the cat command.

    For example, if you downloaded the Times New Roman MT30 font in parts, type the following command to put it back together:

        cat tmrmt30.t01 tmrmt30.t02 > tmrmt30.ttf
    

    Updating the glibc on Caldera eServer 2.3

    There is an incompatibility in the glibc package used by Caldera eServer 2.3; this might cause Java applications to hang when you compile or run a Java application or applet on Caldera eServer 2.3. To download and install an updated version of glibc, see the following Caldera Systems, Inc. Web site:

    1. Select .eServer 2.3 in the list of products and Updates in the list of Categories, and then click Get FAQ.
    2. In the list that is displayed, select item 2. .eServer 2.3 Updates - Updated Package glibc-2.1.2-2S.
    3. Click on one of the links to download the package, and follow the directions provided to upgrade.

    Uninstalling the Runtime Environment for Linux

    The process you use to remove the Runtime Environment for Linux depends on whether you installed the RPM package or the compressed TAR package. See Uninstalling the RPM package or Uninstalling the compressed TAR package for instructions.


    Uninstalling the RPM package

    To uninstall the Runtime Environment for Linux if you installed the RPM package:

    1. At a shell prompt, use the rpm command, as follows:
          rpm -e IBMJava2-JRE
      
      Alternatively a graphical tool such as kpackage or yast2 may be used.
    2. Remove from your PATH statement the directory where you installed the Runtime Environment.

    3. If you installed the Java Plug-in, remove the Java Plug-in files from the Netscape directory.

    Uninstalling the compressed TAR package

    To uninstall the Runtime Environment for Linux if you installed the compressed TAR package:

    1. Remove the Runtime Environment files from the directory where you installed the Runtime Environment.
    2. Remove from your PATH statement the directory where you installed the Runtime Environment.
    3. If you installed the Java Plug-in, remove the Java Plug-in files from the Netscape directory.

    Invoking the Java Runtime Interpreter

    The Runtime Environment for Linux can be invoked from a shell prompt by using the java tool.

    Options for the java tool are as follows:

    The -X options are non-standard and subject to change without notice.


    System properties

    The system property ibm.jvm.bootclasspath can be set using the -D option described in the Invoking the Runtime Interpreter section. The value of this property is used as an additional search path, inserted between any value defined by -Xbootclasspath/p: and the bootclass path. The bootclass path is either the default, or that defined using the -Xbootclasspath: option.


    Obtaining the IBM build and version number

    To obtain the IBM build and version number, type the following at a shell prompt:

      java -version
    

    Euro symbol support

    To take advantage of the euro symbol support, the operating system must support the euro symbol. This might require that you install standard ISO-8859-15 (Latin-9 or Latin-0). For further information, see the HOWTO for your distribution of Linux.

    The following sections give further information on euro symbol support.


    Unicode support

    The Unicode character for the euro is u'20ac'.


    Collation of currency symbols

    Collation of currency symbols traditionally follows the English collation order of the symbol name. Thus cent is followed by dollar. According to this scheme, the euro symbol sorts immediately following the dollar and dong currency symbols and before the French franc.


    Switching the input method in DBCS languages

    On double-byte character set (DBCS) systems, if you want to switch the input method, you must set an environment variable that represents the keycode you use for switching. Optionally, you can set another environment variable that represents the modifiers of the keycode.

    To specify the keycode to use for switching, set the IBMJAVA_INPUTMETHOD_SWITCHKEY environment variable to a keycode definition in the java.awt.event.KeyEvent class, for example, VK_F4.

    Optionally, specify modifiers of the keycode. To specify modifiers of the keycode, set the IBMJAVA_INPUTMETHOD_SWITCHKEY_MODIFIERS environment variable to some combination of the following three mask definitions in the java.awt.event.InputEvent class:

    Separate the masks by commas.

    For example you might set the IBMJAVA_INPUTMETHOD_SWITCHKEY_MODIFIERS environment variable to ALT_MASK, CTRL_MASK.

    During Java initialization, the two environment variables are stored.

    To be sure you have set the environment variables correctly, press a key and check it with the key combination you specified. If it matches, a Java pop-up menu with selectable input methods is displayed.


    Runtime example

    The following Sun Web page might contain a "Hello World" example that you can download. The example demonstrates how to create a simple Java application that runs on and is bundled with the Runtime Environment for Linux. You might find the example at the Sun Web site:

    1. Click Products & APIs.
    2. Click Java(TM) 2 Platform, Standard Edition (J2SE(TM)) under Product Groups.
    3. Click Java(TM) 2 SDK, Standard Edition, v 1.3 under Current Releases.
    4. Click browsing online under J2SE 1.3 Documentation.
    5. Click Notes for Developers under Java Runtime Environment and Java Plug-in.

    The example shows how to make a simple, seamless transition from developing an application with the Developer Kit for Linux, to deploying it with the more lightweight Runtime Environment for Linux.


    Installing your application on a user's system

    After you develop your product and are ready to ship, you need to install your product onto an individual user's system, configure the user's system to support your software, and configure the runtime environment.

    If you use the Runtime Environment for Linux, you must make sure that your installation procedure does not overwrite an existing installation (unless the existing Runtime Environment for Linux is an older version).

    To redistribute the Runtime Environment for Linux, you can install it on your own system, then copy the required Runtime Environment files into your installation set. If you choose this approach, you must include all the files provided with the Runtime Environment for Linux. The Runtime Environment for Linux software can only be redistributed if all files are included. In effect, when you ship your application, it has its own copy of the Runtime Environment for Linux.

    For specific information about the files that must be redistributed, see the license agreement that accompanies this product.


    Runtime Environment for Linux documentation

    IBM supplies the following runtime documentation:


    Known limitations


    Information for Japanese users

    On Japanese versions of Linux, you can use a Japanese input method such as Canna, ATOK12(TM) SE, Wnn4(TM), or Wnn6. Use the following sections to avoid problems when using these Japanese input methods.

    For all input method editor (IME) users

    Canna users

    If you are using the Canna input method with the kinput2 input method server, some visual feedback from the input method is not visible while you are in KIGOU input mode. To avoid the problem, move the focus onto the client window after the Auxiliary Control Window opens.

    ATOK12 SE users

    Wnn4 users

    If you are using Wnn4, the Enter key does not create a new line and a carriage return while the Input Method Editor (IME) is activated. To create a new line and carriage return, deactivate the IME.

    Wnn6 users

    The xwnmo Input Method server is not supported. Use kinput2 as the Input Method server.

    Wnn4, Wnn6 or Canna users

    If you are using kinput2 as the Input Method server, do not minimize or maximize the Java window in which the kinput2 lookup window is displayed.

    If you minimize the Java window:
    When you restore the Java window you can view the kinput2 lookup window, but you cannot access it. If this occurs, restart your Java application.
    If you maximize the Java window:
    When you restore the Java window the lookup window is sometimes located off the screen. If this occurs, do one of the following:

    Notices

    (c) Copyright International Business Machines Corporation 1999, 2001. All rights reserved.

    (c) Copyright Sun Microsystems, Inc. 1997, 2001. 901 San Antonio Rd., Palo Alto, CA 94303 USA. All rights reserved.

    U.S. Government Users Restricted Rights -- Use, duplication or disclosure restricted by GSA ADP Schedule Contract with IBM Corp.

    Consult your local IBM representative for information on the products and services currently available in your area. Any reference to an IBM product, program, or service is not intended to state or imply that only that IBM product, program, or service may be used. Any functionally equivalent product, program, or service that does not infringe any IBM intellectual property right may be used instead. However, it is the users responsibility to evaluate and verify the operation of any non-IBM product, program, or service.

    IBM may have patents or pending patent applications covering subject matter in this document. The furnishing of this document does not give you any license to these patents. You can send license inquiries, in writing, to:

    For license inquiries regarding double-byte (DBCS) information, contact the IBM Intellectual Property Department in your country or send inquiries, in writing, to:

    The following paragraph does not apply to the United Kingdom or any other country where such provisions are inconsistent with local law:

    INTERNATIONAL BUSINESS MACHINES CORPORATION PROVIDES THIS PUBLICATION "AS IS" WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Some states do not allow disclaimer of express or implied warranties in certain transactions, therefore, this statement may not apply to you.

    This information could include technical inaccuracies or typographical errors. Changes are periodically made to the information herein; these changes will be incorporated in new editions of the information. IBM may make improvements and/or changes in the product(s) and/or the program(s) described in this information at any time without notice.

    Any references in this information to non-IBM Web sites are provided for convenience only and do not in any manner serve as an endorsement of those Web sites. The materials at those Web sites are not part of the materials for this IBM product and use of those Web sites is at your own risk.

    IBM may use or distribute any of the information you supply in any way it believes appropriate without incurring any obligation to you.

    Licensees of this program who wish to have information about it for the purpose of enabling (i) the exchange of information between independently created programs and other programs (including this one) and (ii) the mutual use of the information which has been exchanged, should contact:

    Such information may be available, subject to appropriate terms and conditions, including in some cases, payment of a fee.

    The licensed program described in this document and all licensed material available for it are provided by IBM under terms of the IBM Customer Agreement, IBM International Program License Agreement or any equivalent agreement between us.

    Any performance data contained herein was determined in a controlled environment. Therefore, the results obtained in other operating environments may vary significantly. Some measurements may have been made on development-level systems and there is no guarantee that these measurements will be the same on generally available systems. Furthermore, some measurement may have been estimated through extrapolation. Actual results may vary. Users of this document should verify the applicable data for their specific environment.

    Information concerning non-IBM products was obtained from the suppliers of those products, their published announcements or other publicly available sources. IBM has not tested those products and cannot confirm the accuracy of performance, compatibility or any other claims related to non-IBM products. Questions on the capabilities of non-IBM products should be addressed to the suppliers of those products.

    All statements regarding IBM's future direction or intent are subject to change or withdrawal without notice, and represent goals and objectives only.

    All IBM prices shown are IBM's suggested retail prices, are current and are subject to change without notice. Dealer prices may vary.

    This edition applies to the IBM Runtime Environment for Linux, Java 2 Technology Edition, Version 1.3.0 and to all subsequent releases and modifications until otherwise indicated in new editions.


    Trademarks

    The following terms are trademarks of International Business Machines Corporation in the United States, or other countries, or both:

    Java and all Java-based trademarks are trademarks of Sun Microsystems, Inc. in the United States, other countries, or both.

    ATOK is a trademark of JUSTSYSTEM Corporation.

    Wnn is a trademark of OMRON software.

    Other company, product, and service names may be trademarks or service marks of others.