This README file provides information about the IBM zSeries Developer Kit for Linux®, Java(TM) 2 Technology Edition, Version 1.2.2 (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 SuSE Linux 7.0.
The Developer Kit for Linux is a development environment for writing applets and applications that conform to Sun's Java 1.2.2 Core Application Programming Interface (API).
Applets that depend on Sun's Java 1.2.2 APIs work only on browsers that support Java 1.2.2 APIs.
To see the document on compatibility at the click the link and follow the steps below:
X11R6 3.3.x, provided by XFree86 | Currently included in all of the supported products |
C Runtime Library (libc) version 2.1.3-176 or later | Currently included in the supported products.
If you do not have the C Runtime Library (libc) version 2.1.3-176 or later, you must upgrade before using the Developer Kit for Linux. To determine the level of glibc on your system, type the following from within any shell: rpm -q libc |
Linux kernel 2.2.16 or later | Currently included in all of the supported products
If you have a version of the Linux operating system that does not have kernel 2.2.16 or later, information on upgrading the kernel might be found at the following Web site: http://www.kernel.org/ |
The following list describes the contents of the Developer Kit package.
Compiles programs written in the Java programming language into bytecodes (compiled Java code).
Executes Java bytecodes. The Java Interpreter runs programs written in the Java programming language.
Use for testing and running applets.
Helps debug your Java programs.
Disassembles compiled files and prints a representation of the bytecodes.
Parses the declarations and documentation comments in a set of source files and produces a set of HTML pages describing the public and protected classes, interfaces, constructors, methods, and fields. Also produces a class hierarchy and an index of all members.
Attaches native methods to code written in the Java programming language.
Generates signatures for Java Archive (JAR) files and verifies the signatures of signed JAR files.
Manages entities, including their keys, certificates, and the trust associated with them.
Manages a keystore (database) of private keys and their associated X.509 certificate chains authenticating the corresponding public keys.
Creates and modifies the external policy configuration files that define your installation's Java security policy.
Converts a native encoding file to an ASCII file that includes the \udddd Unicode notation.
Generates objects from the names of compiled classes that contain remote object implementations. Includes RMI over Internet Inter-ORB Protocol (IIOP), or RMI-IIOP, support.
Starts the activation system daemon so that objects can be registered and activated in a Java virtual machine (JVM).
Compiles Object Management Group (OMG) Interface Definition Language (IDL) files to Java code.
Starts the CORBA transient naming service.
Creates and starts a remote object registry on the specified port of the current host.
Returns the serialVersionUID for one or more classes in a form that can be copied into an evolving class.
Detects version conflicts between a target jar file and currently installed extension jar files.
The following documentation and demos are included with the Developer Kit for Linux:
Note: This README file and the accompanying license, copyright files, and demo directory are the only documentation included in this Developer Kit for Linux. Click the link and follow the steps below to look at Sun's software documentation by visiting the Sun Web site, or possibly download Sun's Software documentation package:
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 Developer Kit for Linux does not include the IBM just-in-time (JIT) compiler (libjitc.so). The JIT compiler generates machine code dynamically for frequently used bytecode sequences in a Java application or applet while it is running.
All Developer Kit for Linux tools do not use the JIT by default. You cannot enable the JIT.
After you install the Developer Kit for Linux, edit your shell script and add the directory where you installed the Developer Kit to your PATH statement. For more information about the PATH statement, see PATH considerations.
The Developer Kit For Linux can 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 let 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 needed by all users. 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/ associated with the IBM Developer Kit for Linux(R), Java(TM) 2 Technology Edition, Version 1.2.2. Descriptions of the fonts are provided to help you decide which fonts to download.
To install a font, put the file in the /opt/IBMJava2-122/jre/lib/fonts directory.
If you download fonts in parts, you must first put the fonts back together into one file. To put the file back together, be sure it is in the /opt/IBMJava2-122/jre/lib/fonts directory and use the cat command.
For example, if you downloaded the Times New Roman WorldType (for Japan and other countries) font in parts, type the following command to put it back together:
cat tmrmtwt_j.t01 tmrmtwt_j.t02 > tmrmtwt_j.ttf
The process you use to remove the Developer Kit for Linux depends on whether you installed the installable Red Hat Package Manager (RPM) package or the compressed Tape Archive (TAR) package. See Uninstalling the installable Red Hat Package Manager (RPM) package or Uninstalling the compressed TAR package for instructions.
To uninstall the Developer Kit for Linux if you installed the installable RPM package:
rpm -qa | grep IBMThe name of the package is displayed.
rpm -e pkgnamewhere pkgname is the name of the package that was displayed.
To uninstall the Developer Kit for Linux if you installed the compressed TAR package:
To take advantage of the euro symbol support, the operating system must support the euro symbol. To get support for the euro symbol, you might have to 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.
The Unicode character for the euro is u'20ac'.
Collation of currency symbols traditionally follows the English collation order of the symbol name. For example, 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.
The Java 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.
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/IBMJava2-122/bin, you can compile a file named myfile.java by typing the following at a shell prompt:
/opt/IBMJava2-122/bin/javac myfile.java
To avoid typing the full path each time:
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:
The CLASSPATH tells 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, including other versions that you have installed separately, you need to set the CLASSPATH (and PATH) explicitly for each application. If you plan to run multiple applications simultaneously 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, you can use a shell script to switch between the different runtime environments.
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.
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.htmlwhere filename is the name of the HTML file.
For example, http://java.sun.com/applets/NervousText/example1.html is the URL of a Web page that calls an applet. To invoke the Applet Viewer on this Web page, type the following at a shell prompt:
appletviewer http://java.sun.com/applets/NervousText/example1.html
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 (see http://java.sun.com for any legal statements regarding this information):
To obtain the IBM build and version number, type the following at a shell prompt:
java -version
To debug Java programs, you can use the Java Debugger (JDB) application. This debugger communicates with the Java Platform Debugger Architecture (JPDA) provided by the Developer Kit for Linux. For native JNI binary programs, you can still use gdb for debugging.
The JPDA classes are included in the tools.jar file, which must be included in the CLASSPATH when running Java programs that use the JPDA (for example, JDB). Only socket communication is supported on Linux.
A new JDB application is included in the Developer Kit for Linux. The JDB application runs the class com.sun.tools.example.debug.tty.TTY. The Java Virtual Machine Debugging Interface (JVMDI) is now fully supported. The jdb tool included in earlier versions is now included as oldjdb.
The new JDB application uses the JPDA and enables the jdb example tool to attach to a listening Virtual Machine (VM) or to start a new debug session. It is invoked by the jdb command and can be used in the same way as the oldjdb.
You can use the JDB application to debug remote Java applications, including Java applications running on remote machines over a TCP/IP link. To debug a remote Java program, start the java program as follows:
java -Xdebug -Xnoagent -Xrunjdwp:transport=dt_socket,server=y,suspend=y -Djava.compiler=NONE <other args> <myapp> <myapp class args>
The port on which the JPDA is listening is displayed. At the remote debugging machine, type the following:
jdb -attach <machine name or ip address>:<port>
When you launch a debug session using the dt_socket transport, be sure that the specified ports are actually free to use.
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 any 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.
Java Remote Method Invocation (RMI) provides a simple mechanism to do distributed Java programming. RMI over IIOP (RMI-IIOP) extends the base Java RMI capabilities to perform communication using the Common Object Request Broker Architecture (CORBA) standard Internet Inter-ORB Protocol (IIOP protocol). This extension enables direct interaction with any other CORBA Object Request Brokers (ORBs), whether they were implemented in Java or another programming language.
For information about IBM and RMI-IIOP, see the following IBM Web site:
http://www.ibm.com/java/jdk/rmi-iiop/index.html
The following documentation is also available:
The Runtime Environment includes an enhanced BigDecimal class (com.ibm.math.BigDecimal) for Java programming. It is provided (with its supporting class MathContext) as an alternative to the java.math.BigDecimal class.
If you are using the java.math.BigDecimal class in a Java program, and you want to access the class, you must change the import statement in your source code as shown:
Change import java.math.*;
to import com.ibm.math.*;
You do not need to change any other code.
More information about enhanced BigDecimal can be found at the following Web site:
http://www.ibm.com/java/jdk/decimal/
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. You should ensure that a licensed version of the Developer Kit for Linux is installed on the target machine.
If you encounter a problem after you install the Developer Kit for Linux, check the following list:
If you use the Applet Viewer to run an applet that is in the CLASSPATH, you might get an AccessControlException in Swing.
To work around this problem, be sure of the following:
Unable to load libjava.so library
message.
If you receive a message indicating that the libjava.so library could not be loaded because of a symbol not found, you might have a down-level version of the C Runtime Library, libc, installed. The Developer Kit for Linux thread implementation requires libc version 2.1.3-176 or later.
If the Applet Viewer does not load applets, type the following at a shell prompt:
java -verbose sun.applet.AppletViewer
This command lists the classes that are being loaded. From this output, you can determine which class the Applet Viewer is trying to load and where it is trying to load it from. Check to make sure that the class exists and is not damaged.
If you are writing a Java application, particularly a Java Native Interface (JNI) application, be sure that the application handles the EINTR return code correctly; otherwise the application will fail.
The following sections explain known limitations of the Developer Kit for Linux.
The maximum number of threads available is determined by the minimum of:
However, you might run out of virtual storage prior to reaching the maximum number of threads. Click the link and follow the steps below to possibly obtain additional information on adjusting these limits:
public interface interface java.lang.Runnable extends java.lang.Object...
On the Linux X Window System, the keymap is set to: 64 0xffe9 (Alt_L) 0xffe7 (Meta_L), and 113 0xffea (Alt_R) 0xffe8 (Meta_R). You can check this by typing the following at a shell prompt:
xmodmap -pk
This is why the Developer Kit for Linux considers that Meta is being pressed together with Alt. As a workaround, you can remove the Meta_x mapping by typing the following at a shell prompt:
xmodmap -e "keysym Alt_L = Alt_L" -e "keysym Alt_R = Alt_R"
Note: This workaround might affect other X-Windows applications running on the same display if they use the Meta-key that was removed.
This release only supports US English (This needs to be changed)
Install Japanese TrueType font package by TurboLinux Japan. TL390 GA version was released on 12/15/2000. TurboLinux Japan knows that some Japanese applications need this Japanese TrueType font, and they will consider shipping this font package in some way after the GA release.
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If you have purchased a service contract (that is, IBM's Personal Systems Support Line or equivalent service by country), the terms and conditions of that service contract will determine what services, if any, you are entitled to receive with respect to the Program.
This edition applies to the IBM zSeries Developer Kit for Linux, Java 2 Technology Edition, Version 1.2.2 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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