IBM(R) Developer Kit for Linux(R), Java(TM) 2 Technology Edition, Version 1.3.0 README for Preview

This README file provides information about the IBM Developer Kit for Linux(R), Java(TM) 2 Technology Edition, Version 1.3.0 (Developer Kit for Linux.) Use this README file if you want to use the Developer Kit for Linux to write Java applications and applets.

The Developer Kit for Linux has been tested with the following products:

The Developer Kit for Linux has been tested with the following window managers:


Preview Notes

The following is a list of known limitations in the preview release:


Contents

  • Overview
  • Version compatibility
  • Contents of the Developer Kit for Linux
  • The just-in-time (JIT) compiler
  • Configuring the Developer Kit for Linux
  • Installing and configuring the Java Plug-in
  • Installing and registering additional fonts
  • Updating the glibc on Caldera eServer 2.3
  • Uninstalling the Developer Kit for Linux
  • Uninstalling the installable RPM package
  • Uninstalling the compressed TAR package
  • Euro symbol support
  • Unicode Support
  • Collation of Currency Symbols
  • Using the Developer Kit
  • PATH considerations
  • CLASSPATH considerations
  • Running applets with the Applet Viewer
  • Debugging applets with the Applet Viewer
  • Obtaining the IBM build and version number
  • Switching the input method in DBCS languages
  • Shipping Java applications
  • Troubleshooting
  • Known limitations
  • Notices
  • Trademarks

  • Overview

    The Developer Kit for Linux is a development environment for writing applets and applications that conform to Sun's Java 1.3 Core Application Programming Interface (API).


    Version compatibility

    In general, any applet or application that runs in Version 1.1.8 of the Developer Kit for Linux should run correctly in this version. Applets that depend on Sun's Java 1.3 APIs work only on browsers that support Java 1.3 APIs.

    For more details, see the document on compatibility at the following Sun Web site:


    Contents of the Developer Kit for Linux

    The following list describes the contents of the Developer Kit for Linux.

    RUNTIME - Core Classes (rt.jar)

    This file contains all of the compiled .class files for the platform and must remain zipped for the compiler and interpreter to properly access the class files within it.

    SOURCE FILES - Public Classes (javasrc.jar)

    These are the source files used to create the core classes that are included in the classes.zip file. These source files are provided for information only, to help developers learn to use the Java programming language.

    Do not modify these classes; instead, create subclasses and override where you need to.

    TOOLS
    The tools provided include:

    JAVA DOCUMENTATION AND DEMOS

    The following documentation and demos are included with the Developer Kit for Linux:

  • README:

    This file.

  • COPYRIGHT:

    Copyright notice for the Developer Kit for Linux software.

  • LICENSE:

    The LICENSE.SDK.HTML file contains the license agreement for the Developer Kit for Linux software.

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

  • FIXES.LST:

    A text file that describes any defects fixed after the initial release of this version.

  • Note: This README file and the accompanying license, copyright files, demo directory, and source code (javasrc.jar) are the only documentation included in this Developer Kit for Linux. You can look at Sun's software documentation by visiting the Sun Web site, or you might be able to download Sun's Software documentation package from the following Sun Web site:

    The documentation package is designed to be extracted into the Developer Kit for Linux software installation directory. If you download the zip file archive version, be sure to preserve the file path names when you extract the files from the archive. If you use pkunzip, specify the -d option.


    The just-in-time (JIT) compiler

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

    All Developer Kit for Linux tools use the JIT 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 determine if the JIT is enabled, type the following at a shell prompt:

    If a JIT is in use, one of the following messages is displayed:

    If no JIT is in use, one of the following messages is displayed:


    Configuring the Developer Kit for Linux

    After you install the Developer Kit for Linux, edit your shell script and add to your PATH statement the directory where you installed the Developer Kit. For more information about the PATH statement, see PATH considerations.


    Installing and configuring the Java Plug-in

    The Java Plug-in is a Web browser plug-in for use with Netscape Communicator for Linux. If you use the Java Plug-in, you can bypass your Web browser's default Java Virtual Machine and use instead a Java Runtime Environment (JRE) for running applets or beans in the browser.

    To install and configure the Java Plug-in:


    Installing and registering additional fonts

    After installation, if you downloaded additional fonts, you can install and register them. If you downloaded the fonts in parts, you must first put them back together into one file for each font.

    Note: Asian characters cannot be displayed, even in the Asian locale, if you do not have the Times New Roman MT30 font installed on your system. Therefore, at a minimum, you must download the Times New Roman MT30 font to display Asian characters.

    To put a font file back together, 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
    

    To install the additional fonts, copy them to the /opt/IBMJava2-13/jre/lib/fonts directory.


    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 Developer Kit for Linux

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


    Uninstalling the installable RPM package

    To uninstall the Developer Kit for Linux if you installed the installable RPM package:

    1. At a shell script, type the following:
          rpm -qa | grep IBM
      
      The name of the package is displayed.

    2. Use the rpm command, as follows:
          rpm -e pkgname
      
      where pkgname is the name of the package that was displayed.
    3. Modify your shell script. Remove from your PATH statement the directory where you installed the Developer Kit.

    4. 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 Developer Kit for Linux if you installed the compressed TAR package:

    1. Remove the Developer Kit files from the directory where you installed the Developer Kit.
    2. Modify your shell script. Remove from your PATH statement the directory where you installed the Developer Kit.
    3. If you installed the Java Plug-in, remove the Java Plug-in files from the Netscape directory.

    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.


    Using the Developer Kit

    The main Developer Kit for Linux tools are programs that are run from a shell prompt; they do not have a Graphical User Interface (GUI).

    The following sections give information on using the Developer Kit for Linux.


    PATH considerations

    After installing the Developer Kit for Linux software, you can run a tool by typing its name at a shell prompt with a filename as an argument.

    You can specify the path to a tool by typing the path before the name of the tool each time. For example, if the Developer Kit for Linux software is installed in /opt/IBMJava2-13/bin, you can compile a file named myfile.java by typing the following at a shell prompt:

      /opt/IBMJava2-13/bin/javac myfile.java
    

    To avoid typing the full path each time:

    1. Add the following directories to the PATH environment variable:

    2. Compile the file with the javac tool. For example, compile the file myfile.java by typing the following at a shell prompt:

        javac myfile.java
      

    The PATH environment variable enables Linux to find executable files, such as javac, java, and javadoc, from any current directory. To display the current value of your PATH, type the following at a shell prompt:

      echo $PATH
    

    To change the PATH environment variable:

    1. Edit your shell startup file (usually .bash_profile, .profile, or .login depending on the shell) and add to the PATH environment variable the absolute paths to the following directories:
    2. Log on again or run the updated shell script to activate the new PATH setting.

    CLASSPATH considerations

    The CLASSPATH tells the Runtime Environment for Linux and the Developer Kit for Linux tools, such as java, javac, and javadoc, where to find the Java class libraries. If you keep the bin and lib directories under the same parent directory level, the executable files can find the classes.

    You need to explicitly set the CLASSPATH only if one of the following applies:

    To display the current value of your CLASSPATH, type the following at a shell prompt:

      echo $CLASSPATH
    

    If you plan to develop and run applications using different runtime environments, you need to explicitly set the CLASSPATH (and PATH) appropriately for each application. If you plan to simultaneously run multiple applications using different runtime environments, be sure each application is run in its own shell.

    If you want to run only one version of Java at a time, a shell script can be used to switch between the different runtime environments.


    Running applets with the Applet Viewer

    With the Applet Viewer, you can run one or more applets that are called by reference in a Web page (HTML file) using the APPLET tag. The Applet Viewer finds the APPLET tags in the HTML file and runs the applets, in separate windows, as specified by the tags.

    Because the Applet Viewer is for viewing applets, it cannot display an entire Web page that contains numerous HTML tags. It parses only the APPLET tag and no other HTML on the Web page.

    To run an applet with the Applet Viewer, type the following at a shell prompt:

       appletviewer name
    

    where name is one of the following:

    For example, to invoke the Applet Viewer on an HTML file that calls an applet, type the following at a shell prompt:

      appletviewer $HOME/filename.html
    
    where filename is the name of the HTML file.

    For example, to invoke the Applet Viewer on a URL-based Web page that calls an applet, type the following at a shell prompt:

      appletviewer http://java.sun.com/applets/NervousText/example1.html
    

    Debugging applets with the Applet Viewer

    You can debug applets using the -debug option of Applet Viewer. When debugging applets, it is best to invoke Applet Viewer from the directory that contains the HTML file that calls the applet. For example:

         cd demo/TicTacToe
         ../../bin/appletviewer -debug example1.html
    

    You might find documentation on the debugger and its API at the following Sun Web site:


    Obtaining the IBM build and version number

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


    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 some 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 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 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.


    Shipping Java applications

    A Java application, unlike a Java applet, cannot rely on a Web browser for installation and runtime services. When you ship a Java application, your software package probably consists of the following parts:

    To run your application, a user needs the Runtime Environment for Linux. The Developer Kit for Linux software contains a runtime environment. However, you cannot assume that your users have the Developer Kit for Linux software installed.

    Your Developer Kit for Linux software license does not allow you to redistribute the Developer Kit for Linux software files. The Runtime Environment for Linux is available for redistribution as a separate package. You can download the Runtime Environment for Linux from the Web site where you obtained the Developer Kit for Linux.


    Troubleshooting

    If you encounter a problem after you install the Developer Kit for Linux, check the following list:


    Known limitations


    Notices

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

    Copyright International Business Machines Corporation 2000. All rights reserved.

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    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.

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

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    All rights reserved.

    (c) Copyright IBM Corporation 2000. All rights reserved.