README Java(tm) Development Kit JDK(tm) 1.1.8 Software Updates to these release notes will be posted on the Java Software website: http://java.sun.com/products/jdk/1.1/README-update.html ----------------------------------------------------------------------- CONTENTS Overview of the Java Development Kit - Introduction - Version Compatibility - Bug Fixes - What the JDK Software Contains - Where to Find More Information - Submitting Comments - Reporting Bugs and Requesting Features - JavaBeans(tm) and the Beans Development Kit Installing and Running the JDK Software - Installation Notes - Windows - Running JDK Tools in Microsoft Windows - Microsoft Windows PATH and CLASSPATH - Using the JIT Compiler - Microsoft Windows Installation Troubleshooting - Possible Problems with Winsock - Solaris - Running JDK Tools in Solaris - Solaris PATH and CLASSPATH - Solaris Installation Troubleshooting - Running Applets with the AppletViewer - Debugging Programs with the Debugger - Java Plug-in Compatibility Class Load Hook - Configuring a Class Load Hook - The Class Load Hook API Euro Support - Encodings and Euro Support - Locales and Euro Support Data Transfer Problems on Windows Deploying Java Applications - Runtime Environment - Installation ======================================================================= OVERVIEW OF THE JAVA DEVELOPMENT KIT ======================================================================= ----------------------------------------------------------------------- INTRODUCTION ----------------------------------------------------------------------- The Java Development Kit is a development environment for writing applets and applications that conform to the Java 1.1 platform. Its compiler and other tools are run from a shell and have no GUI interface. This version includes improvements in functionality, performance, and quality over version 1.0.2 of the Java platform, including bug fixes since the previous release of the 1.1 platform. This is a maintenance release. Changes made to the JDK software since the first 1.1 beta release are in the file named CHANGES. Because there are no API changes in maintenance releases, we continue to refer to this platform as the Java platform 1.1 rather than 1.1.8. While bugs have been fixed in version 1.1.8, the platform hasn't changed. A Symantec JIT bytecode compiler is included in the Windows version of this JDK software. The Symantec JIT compiler is copyrighted (c), 1996-1999, by Symantec Corporation. All rights reserved. All tools in the Windows version of the JDK software use the JIT by default. To disable the JIT, see "Using the JIT," below. The Java platform 1.1 offers capabilities over the 1.0 platform: Internationalization, signed applets, JAR file format, AWT (window toolkit) enhancements, JavaBeans(tm) component model, networking enhancements, Math package for large numbers, Remote Method Invocation (RMI), Reflection, database connectivity (JDBC), new Java Native Interface, Object Serialization, Inner Classes, and performance enhancements. For further description of these features, see the "New Feature Summary" in the JDK documentation. As part of our ongoing effort to improve the quality of the JDK software, we will continue to fix bugs and develop new features. In order to help us prioritize our bug-fixing effort, please submit any bugs you find as soon as possible, using the procedure described in the "Reporting Bugs" section below. The Java Development Kit is a product of Sun Microsystems, Inc. ----------------------------------------------------------------------- VERSION COMPATIBILITY ----------------------------------------------------------------------- In general, any applet or application that ran in previous versions of the Java Development Kit should run correctly in version 1.1.8. A failure to do so is a bug, except for a small number of cases where compatibility has had to be broken to close potential security holes or fix implementation or design bugs. Of course, applets that depend on any new 1.1 APIs will not work on any browsers that support only 1.0.2, such as Internet Explorer 3.0 and Netscape 3.0. However, in general, applets relying only on APIs defined in 1.0.2 (but compiled with the JDK 1.1 compiler) will run on 1.0.2 browsers. This "downwards" compatibility has not been extensively tested and cannot be guaranteed. For more details, see the document on compatibility at: http://java.sun.com/products/jdk/1.1/compatibility.html If you find any such incompatibilities that are not listed on the Compatibility web page, please report them to us as noted below under "Reporting Bugs," and mention that they are compatibility bugs. Compatibility is critically important to us, and a cornerstone of the promise: Write Once, Run Anywhere(tm). ----------------------------------------------------------------------- BUG FIXES ----------------------------------------------------------------------- As with any release, we will continue vigorously testing and debugging the JDK software. If we uncover any important bugs, we will post them on the Java Developer Connection(sm) web site at: http://java.sun.com/jdc/bugParade/index.html Bugs that are fixed in each 1.1.x release of the JDK are listed at: http://java.sun.com/products/jdk/1.1/bugs.html As always, your comments and bug reports are important to making future releases successful. We will use your feedback to help plan future releases. Please report bugs, request features and submit comments using the procedure noted below in the sections "Submitting Comments" and "Reporting Bugs and Requesting Features". ----------------------------------------------------------------------- WHAT THE JDK SOFTWARE CONTAINS ----------------------------------------------------------------------- RUNTIME ---------------------------------------------------------- - Core Classes (classes.zip) DO NOT UNZIP THIS FILE! It must remain zipped for the compiler and interpreter to access the class files within it properly. This file contains all of the the compiled .class files for the platform. SOURCE FILES ----------------------------------------------------- - Source Files for Public Classes (src.zip file or src directory) This is the set of source files used to create the classes included in the core classes classes.zip file (above). These source files are provided for information purposes only, to help developers learn and use the Java programming language. They do not include the private java.* classes or the sun.* classes, and therefore cannot be compiled into a complete classes.zip file. Do not modify these classes; instead, create subclasses and override where you need to. How this is installed depends on the platform: - On Microsoft Windows platforms, the source files are automatically unzipped for you during installation. - On Solaris, you must unzip the src.zip file yourself. You can get a free copy of the correct version of unzip in source form (which you must compile) from: http://www.cdrom.com/pub/infozip/zlib/ or ftp://ftp.cdrom.com/pub/infozip/zlib/ or ftp://ftp.uu.net/pub/archiving/zip/UNIX/SUN/ TOOLS ------------------------------------------------------------ - Java Compiler (javac) Compiles programs written in the Java programming language into bytecodes. - Java Interpreter (java) Executes Java bytecodes. In other words, it runs programs written in the Java programming language. - Jave Runtime Interpreter (jre) Similar to the Java Interpreter (java), but intended for end users who do not require all the development-related options available with the java tool. - Java AppletViewer (appletviewer) Used for testing and running applets. - Java Debugger (jdb) Helps you find bugs in programs. - Class File Disassembler (javap) Disassembles compiled files and prints out a representation of the bytecodes. - Java Documentation Generator (javadoc) 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. - C Header and Stub File Generator (javah) For attaching native methods to code written in the Java programming language. - Java Archive Tool (jar) Combines many class files and other resources into a single jar file. - Digital Signing Tool (javakey) Manages entities, including their keys, certificates, and the trust associated with them. - Native-To-ASCII Converter (native2ascii) Converts a native encoding file to an ascii file that includes the \udddd Unicode notation. - Java RMI Stub Converter (rmic) Generates objects from the names of compiled classes that contain remote object implementations. - Java Remote Object Registry (rmiregistry) Creates and starts a remote object registry on the specified port of the current host. - Serial Version Command (serialver) Returns the serialVersionUID for one or more classes in a form suitable for copying into an evolving class. - AWT 1.1 Conversion Tool (updateAWT) Included with the JDK AWT documentation, rather than in the bin directory. Updates deprecated 1.0 AWT names to new 1.1 AWT names (for Sun Solaris and UNIX systems, or Windows systems with the MKS toolkit). - Various C libraries and include files JAVA DOCUMENTATION AND DEMOS ------------------------------------------ - demo directory awt-1.1 AWT demos i18n Internationalization demos Animator General-purpose animator ArcTest Test arc drawing and filling BarChart Simple bar-chart applet Blink Blinking, multicolored text CardTest Test card layout manager Clock Analog clock DitherTest Test image dithering DrawTest Draw points and lines Fractal Fractal figures GraphLayout Graph layout by iterated relaxation GraphicsTest Test graphics operations ImageMap Live-feedback image map JumpingBox Catch the jumping box MoleculeViewer Three-dimensional chemical model viewer NervousText Nervous text SimpleGraph Draw a simple graph SortDemo Animated sorting algorithms SpreadSheet Simple spreadsheet TicTacToe Tic-tac-toe game WireFrame Three-dimensional wire-frame model viewer RMI demos are available in the separately-downloadable JDK documentation. See the entry "Demonstration Applets and Applications" in the JDK documentation table of contents for access. - README This file you are currently reading - CHANGES Changes made in the beta and final releases - COPYRIGHT Copyright notice for the JDK software - LICENSE License agreement for the JDK software NOTE: The JDK software does not include the HotJava(tm) Browser. To obtain the HotJava Browser, see: http://java.sun.com/products/hotjava/ ----------------------------------------------------------------------- WHERE TO FIND MORE INFORMATION ----------------------------------------------------------------------- This README file and the accompanying CHANGES, LICENSE, COPYRIGHT files, demo directory, and source code (src.zip) are the only documentation included in this JDK software bundle. You can browse the JDK documentation by visiting the Java Software web site, or you can download the JDK Documentation Bundle from: http://java.sun.com/products/jdk/1.1/ The JDK Documentation Bundle includes: - Release Notes - API Reference - Guide to New Features - Additional Demo Programs - Demo Overview Page - Tools Documentation The Documentation Bundle is designed to be extracted into the JDK software installation directory. If you download the ZIP archive version, be sure to preserve the file path names when you extract the files from the archive. (With pkunzip, specify the -d option.) If you are new to the Java programming language, you will want to browse or download the Java Tutorial at: http://java.sun.com/docs/books/tutorial/ For a comprehensive list of online documentation, go to the Java Software Documentation page at: http://java.sun.com/docs/ ----------------------------------------------------------------------- SUBMITTING COMMENTS ----------------------------------------------------------------------- We are very interested in receiving your comments and suggestions as early as possible. If you have a specific feature request or bug to report, please refer to the next section for how to submit it. Send other comments and informal suggestions directly to us at our JavaSoft email addresses at Sun, which are listed at: http://java.sun.com/mail/ While we are not able to respond individually to each email message, we do review all comments. ----------------------------------------------------------------------- REPORTING BUGS AND REQUESTING FEATURES ----------------------------------------------------------------------- To report bugs or feature requests, go to this web page: http://java.sun.com/cgi-bin/bugreport.cgi This gives you instructions for checking if your bug is a duplicate by allowing you to look in our known bugs list. This also gives instructions for how to submit bugs and request features. When submitting a bug, be sure you include the version number of the JDK software you are running. You can get the version number of the JDK software by executing: java -version ----------------------------------------------------------------------- JAVABEANS(tm) AND THE BEANS DEVELOPMENT KIT ----------------------------------------------------------------------- A version of the Beans Development Kit (BDK) is also available for immediate download from Java Software. BDK includes specific tools and support for JavaBeans developers such as the BeanBox test containers and example beans. See: http://java.sun.com/beans/bdk_download.html Updates to the BDK, tools, and general JavaBeans information will be posted on a regular basis to the JavaBeans web site: http://java.sun.com/beans ======================================================================= INSTALLING AND RUNNING THE JDK SOFTWARE ======================================================================= ----------------------------------------------------------------------- INSTALLATION NOTES ----------------------------------------------------------------------- IMPORTANT: Please make sure you understand the Copyright and License information (in the files named COPYRIGHT and LICENSE) before installing this release. The JDK software and documentation are available in two separate downloadable compressed files, called "bundles". They need to be downloaded separately into the same directory and unpacked as follows for the few html links between them to work. Here are the abbreviated instructions. (The installation procedure is different on different platforms, so these instructions are quite general.) 1. Go to the download page for the Java Development Kit and download the software and documentation separately: http://java.sun.com/products/jdk/1.1/ 2. Follow the installation instructions for your particular platform at: http://java.sun.com/products/jdk/1.1/installation-solaris2.html OR http://java.sun.com/products/jdk/1.1/installation-win32-x86.html 3. Unpack the software and documentation bundles according to the instructions on the web page given in step 2. You should end up with the directory structure shown below. 4. Set the PATH and CLASSPATH for Windows or Solaris as described in the section that follows. 5. If you have installed the documentation bundle, use a web browser to go to your new, local JDK documentation table of contents by opening the "index.html" file in the "docs" directory. jdk1.1.8 _________________________|_____________________________________ | | | | | | | | | | | README CHANGES COPYRIGHT LICENSE bin lib include demo src docs index.html | | | | | | | _____________________________|_____ | | | | | api tooldocs relnotes guide index.html | | | | The "src" directory shown above originally appears as a "src.zip" file in the Solaris installation, which you must manually unzip. On Windows, the installer automatically unzips it for you. The "docs" directory will be present only if you download and install the JDK documentation, available at http://java.sun.com/products/jdk/1.1/docs.html ----------------------------------------------------------------------- RUNNING JDK TOOLS IN MICROSOFT WINDOWS ----------------------------------------------------------------------- After installing the JDK software, you start a tool by typing its name into the DOS window with a filename as an argument. None of the main JDK tools have with GUI interfaces -- they are all run from the DOS command line. (For example, if you double-click on the compiler "javac" icon, it will briefly open and immediately close a DOS window, because that is not the proper way to run it.) You can specify the path to a tool either by typing the path in front of the tool each time, or by adding the path to the startup file (autoexec.bat). For example, if the JDK software is installed at C:\jdk1.1.8, to run the compiler on a file myfile.java, go to a DOS shell and execute this: Type: C:\jdk1.1.8\bin\javac myfile.java -or- Add C:\jdk1.1.8\bin to your path statement Type: javac myfile.java See the next section about setting the PATH and CLASSPATH variables. ----------------------------------------------------------------------- MICROSOFT WINDOWS PATH and CLASSPATH ----------------------------------------------------------------------- Windows NT only - If you are using Windows NT, it is preferable to make the following environment variable changes in the Control Panel. Start the Control Panel, select System, then edit the environment variables. 1. PATH - You may want to set the PATH variable for convenience. Add the absolute path of the "jdk1.1.8\bin" directory to your PATH statement as follows. The PATH statement enables Windows to find the executables (javac, java, javadoc, etc.) from any current directory. To find out the current value of your PATH, at the DOS prompt type: C:\> path To change the PATH, open the AUTOEXEC.BAT file and make the change to the PATH statement. To edit the AUTOEXEC.BAT file in Microsoft Windows 95 or Microsoft Windows 98: i. Start a text editor by choosing "Start", "Programs", "Accessories", and choosing WordPad or NotePad. ii. Choose Open from the File menu and type "c:\autoexec.bat" for the filename This will open the file for editing. iii. Look for the PATH statement. Notice that the PATH statement is a series of directories separated by semi-colons (;). Windows looks for programs in the PATH directories in order, from left to right. Look for other versions in the PATH. There should only be one path to a classes.zip file. When in doubt, put the java directory at the end of the path statement. For example, in the following PATH statement, we have added the java directory at the end: PATH C:\WINDOWS;C:\WINDOWS\COMMAND;C:\;C:\DOS;C:\JDK1.1.8\BIN To make the path take effect, execute the following: C:\> autoexec.bat 2. CLASSPATH Environment Variable The CLASSPATH environment variable tells the Java development tools where to find Java class files such as those in classes.zip and any class files used by applications that you write. If the CLASSPATH environment variable is not set, the following is used as a default class path: .;[bin]\..\classes;[bin]\..\lib\classes.zip In this expression, [bin] is substituted by the absolute path to the jdk1.1.8\bin directory. Note that this default class path includes '.', the current directory and the classes.zip file for the Java platform api. This means that you do not have to (and shouldn't) set the CLASSPATH environment variable when the .class files you want to use are all in the current directory. UNSETTING CLASSPATH If you have previously set the CLASSPATH and want to unset it, you normally need to change the current value (at the command line) and the startup value (in a startup file or script). For example, to see if it is currently set, type: % set This lists all of the environment variables. CLASSPATH will not appear if it is not set. If it is set, you can unset the current value by setting it to no value: % set CLASSPATH= Also open your startup file (autoexec.bat) or script and remove the path to the Java platform classes from the CLASSPATH environment variable, if you want the change to be permanent. Refer to the Windows Installation Troubleshooting section below if you have problems running the JDK software. For more information on the CLASSPATH environment variable, see the Java Software web site: http://java.sun.com/products/jdk/1.1/docs/tooldocs/win32/classpath.html ----------------------------------------------------------------------- USING THE JIT COMPILER ----------------------------------------------------------------------- The Win32 Just In Time (JIT) bytecode compiler converts virtual machine bytecodes to native instructions before execution. This can cause some delay in program startup and class file loading, but can also reduce overall program execution time by a factor of ten. In the Win32 version of the Java Development Kit, the JIT is part of the JDK software and is invoked by default. Should you ever want to disable the JIT compiler, you can do so by setting the java.compiler property to NONE: java -Djava.compiler=NONE MyClass This method of disabling the JIT compiler works with both this release of the Java Development Kit and with the JDK 1.2 software. It is the recommended method for disabling the JIT. In this version of the Java Development Kit, you can also disable the JIT compiler by using the -nojit command-line option: java -nojit MyClass jre -nojit MyClass Some JDK tools, such as appletviewer, run by invoking a launcher. To use these tools without the JIT, uses the -J option to pass the -nojit option to the launcher: appletviewer -J-nojit mypage.html With the java tool, setting JAVA_COMPILER also affects JIT usage. The jre tool ignores JAVA_COMPILER. Both tools also use the java.compiler property to determine JIT usage. See the appropriate tool documentation. ----------------------------------------------------------------------- MICROSOFT WINDOWS INSTALLATION TROUBLESHOOTING ----------------------------------------------------------------------- Here are four troubleshooting tips for Microsoft Windows. * If you see the following error message net.socketException: errno = 10047 -or- Unsupported version of Windows Socket API check which TCP/IP drivers you have installed. The AppletViewer supports only the Microsoft TCP/IP drivers included with Windows 95. If you are using third-party drivers (e.g., Trumpet Winsock), you'll need to change over to the native Microsoft TCP/IP drivers if you want to load applets over the network. * If the AppletViewer does not load applets then you might try the following: 1. set HOMEDRIVE=c: set HOMEPATH=\ and restart the AppletViewer (in the same DOS box) 2. set HOME=c:\ and restart the AppletViewer (in the same DOS box) If none of these work, try: java -verbose sun.applet.AppletViewer This lists the classes that are being loaded. From this output, you can determine which class the AppletViewer is trying to load and where it's trying to load it from. Check to make sure that the class exists and is not corrupted in some way. * Error Message: "Exception in thread NULL" or "Unable to initialize threads: cannot find class java/lang/Thread" If you are getting one of these fatal error messages when running java, javac, or appetviewer, you should check your CLASSPATH environment variable. It may list "c:\java" or the "classes" directory from an older release. You can either unset the CLASSPATH variable, or set it to include only the latest version of the Java platform class library. For example: C:\> set CLASSPATH=.;C:\jdk1.1.8\lib\classes.zip This will make sure that you are using the correct classes for this release. * Cannot close AppletViewer copyright window (Windows 95 only) In Microsoft Windows 95, the launch bar may partially cover the AppletViewer copyright notice window Accept and Reject buttons. If this happens, you can move the Windows 95 launch bar to the side of the desktop to allow access to the copyright window Accept and Reject buttons. ----------------------------------------------------------------------- POSSIBLE PROBLEMS WITH WINSOCK ----------------------------------------------------------------------- When installing the JDK software on a Windows 95 system, the installer will check to see if Winsock 2 is installed on the system. Winsock 2 is the most recent version of the networking layer (Winsock) for Windows and is published by Microsoft. If Winsock 2 isn't installed, the installer will offer to install it. Winsock 2 is advertised as being fully backward compatible with Winsock 1.1, its predecessor. Occasionally, however, some Microsoft Windows configurations seem be adversely affected after installing Winsock 2. Problems that have been reported include networking programs (such as news and mail readers, browsers, etc) that stop working or even start crashing. If this happens on your system, you should remove Winsock 2 from your system. This is a simple, three-step procedure: 1. go to C:\Windows\WS2BAKUP directory 2. run the WS2BAKUP.BAT script 3. reboot your machine Even without Winsock 2, the JDK software will continue to work properly. In heavy multi-tasked network applications such as servers, Winsock 1.1 bugs may manifest themselves. Most other applications will be unaffected. We recommend that you upgrade to Winsock 2 as soon as possible. ----------------------------------------------------------------------- RUNNING JDK TOOLS IN SOLARIS ----------------------------------------------------------------------- After installing the JDK software, you start a tool by typing its name into a shell window with a filename as an argument. You can specify the path to a tool either by typing the path in front of the tool each time, or by adding the path to the startup file. For example, if the JDK software is installed at /usr/local/jdk1.1.8, to run the complier on a file myfile.java, go to a shell and execute: Type: /usr/local/jdk1.1.8/bin/javac myfile.java -or- Add /usr/local/jdk1.1.8/bin to your path statement Type: javac myfile.java The path and CLASSPATH variables are not required, but it is helpful to know more about them. See the next section about setting these variables. ----------------------------------------------------------------------- SOLARIS PATH and CLASSPATH ----------------------------------------------------------------------- 1. PATH Variable - You may want to update your PATH environment variable for convenience. Add the absolute path of the "jdk1.1.8/bin" directory to your Unix path variable, as follows. The path variable enables Solaris to find the executables (javac, java, javadoc, etc.) from any current directory. To find out if the path is currently set for any java tools, execute: % which java This will print the path to java, if it can find it. If you use the C shell (csh), you can set the path in your startup file (~/.cshrc) as follows, for example: set path=($path /usr/local/jdk1.1.8/bin) Then load the startup file and verify that the path is set by repeating the "which" command above: % source ~/.cshrc % which java 2. CLASSPATH Environment Variable The CLASSPATH environment variable tells the Java development tools where to find Java class files such as those in classes.zip and any class files used by applications that you write. If the CLASSPATH environment variable is not set, the following is used as a default class path: .;[bin]\..\classes;[bin]\..\lib\classes.zip In this expression, [bin] is substituted by the absolute path to the jdk1.1.8\bin directory. Note that this default class path includes '.', the current directory and the classes.zip file for the Java platform api. This means that you do not have to (and shouldn't) set the CLASSPATH environment variable when the .class files you want to use are all in the current directory. UNSETTING CLASSPATH If you have previously set the CLASSPATH and want to unset it, you normally need to change the current value (at the command line) and the startup value (in a startup file or script). For example, to see if it is currently set, type: % echo $CLASSPATH If it is set, you can unset the current value by typing: % unsetenv CLASSPATH Also open your startup file (~/.cshrc) or script and remove the path to the JDK classes from the CLASSPATH environment variable if you want the change to be permanent. Refer to the Solaris Installation Troubleshooting section below if you have problems running the JDK software. See the Java Software web site for more information about the CLASSPATH environment variable: http://java.sun.com/products/jdk/1.1/docs/tooldocs/solaris/classpath.html ----------------------------------------------------------------------- SOLARIS INSTALLATION TROUBLESHOOTING ----------------------------------------------------------------------- * Error Message: "Exception in thread NULL" or "Unable to initialize threads: cannot find class java/lang/Thread" If you are getting one of these fatal error messages when running java, javac, or appetviewer, you should check your CLASSPATH environment variable. It may list "java" or the "classes" directory from an older release. You can either unset the CLASSPATH variable, or set it to include only the latest version of the Java platform class library. For example: % setenv CLASSPATH .:/usr/local/jdk1.1.8/lib/classes.zip This will ensure that you are using the correct classes for this release. ----------------------------------------------------------------------- RUNNING APPLETS WITH THE APPLETVIEWER ----------------------------------------------------------------------- AppletViewer allows you to run one or more applets that are called by reference in a web page (HTML file) using the APPLET tag. The AppletViewer finds the APPLET tags in the HTML file and runs the applets (in separate windows) as specified by the tags. AppletViewer is for viewing applets. It cannot display an entire web page that contains many HTML tags. It parses only the APPLET tag and no other HTML on the web page. To run an applet with appletviewer, you go to a command line for your operating system and run appletviewer, passing in the filename or URL of the web page as its argument. _______ SOLARIS Here is an example of how to invoke AppletViewer on a file-based web page in Solaris. First change to the "jdk1.1.8" directory. Then execute: bin/appletviewer demo/GraphLayout/example1.html Here is an example of how to invoke AppletViewer on a URL-based web page in Solaris. Execute: bin/appletviewer http://java.sun.com/applets/NervousText/example1.html _______ WINDOWS Here is an example of how to invoke AppletViewer on a file-based web page in Windows. Go to a DOS prompt, change to the "jdk1.1.8" directory and then execute: bin\appletviewer demo\GraphLayout\example1.html Here is an example of how to invoke AppletViewer on a URL-based web page in Windows. Execute: bin\appletviewer http://java.sun.com/applets/NervousText/example1.html ___________________________ INNER CLASSES AND JAR FILES Many users have reported problems using appletviewer to run applets when the applet classes are located in a JAR file. The applet class throws an IllegalAccessError when trying to access its own inner class. The same applet runs without error when all the class files are located on the file system. This error occurs because the main applet class and the applet inner class have different class loaders. This can happen when the JAR file and the original class files are located in the same directory. It can also happen when the same JAR file is passed to appletviewer twice: once as an ARCHIVE attribute in an APPLET tag, and again in the class path. In both cases, the applet class loader loads the applet class, while the system class loader loads the inner class. When running an applet from a JAR file, make sure that the classes files are only available in the JAR file, and that the JAR file is not in the class path. This problem only occurs on the Java 1.1 platform. On the Java 1.2 platform, improvements in the class loading mechanism avoid this problem. ----------------------------------------------------------------------- DEBUGGING PROGRAMS WITH THE DEBUGGER (JDB) ----------------------------------------------------------------------- You can debug applets using the -debug option of appletviewer. When debugging applets, it's best to invoke appletviewer from the directory that contains the applet's HTML file. For example, on Solaris: cd demo/TicTacToe ../../bin/appletviewer -debug example1.html On the PC: cd demo\TicTacToe ..\..\bin\appletviewer -debug example1.html You can find documentation on the debugger and its API at: http://java.sun.com/products/jdk/1.1/debugging/ ======================================================================= CLASS LOAD HOOK ======================================================================= This release supports use of a class load hook, a native-code function called when each class is loaded. A class load hook can modify the class data to include profiling or debugging information. This feature was requested by development tool vendors. Support for a class load hook is a temporary feature and is subject to change. Class load hook support is not part of the Java platform specification and will not be available in any 1.2 version of the JDK software. JDK 1.2 software includes profiling and debugging features that are more powerful and general. ----------------------------------------------------------------------- Configuring a Class Load Hook ----------------------------------------------------------------------- If the environment variable _CLASSLOAD_HOOK is set, its value should be the basename of a native code library. For example, if the value of _CLASSLOAD_HOOK is "myhook", the runtime looks for a Windows library called myhook.dll or a Solaris library called myhook.so. The location of the library depends on the system platform: * On Windows, the runtime looks in the bin directory of the JDK installation, then in each directory in the PATH environment variable. * On Solaris, the runtime look in the lib directory of the JDK installation, then in each directory in the LD_LIBRARY_PATH environment variable. ----------------------------------------------------------------------- The Class Load Hook API ----------------------------------------------------------------------- The class load hook library must export the following function: typedef struct { unsigned char *class_data; int class_data_len; unsigned char *new_class_data; int new_class_data_len; void * (*malloc_f)(int); } classload_event; void ClassLoadHook(classload_event *); The runtime calls ClassLoadHook() after it obtains the class file data but before it constructs the in-memory class representation. ClassLoadHook() is passed the existing class file data (via class_data and class_data_len), and a pointer to a memory allocation function (via malloc_f). ClassLoadHook() should use the memory allocation function to create a new buffer for the modified class file data and return it via new_class_data and new_class_data_len. If ClassLoadHook() chooses not to modify a class, it should set new_class_data to NULL. The runtime is responsible for deallocating the modified class file data buffer. ======================================================================= EURO SUPPORT ======================================================================= This release of the Java Development Kit includes support for the new European Union curreny, the euro. For details, see the Euro Support file online at http://java.sun.com/products/jdk/1.1/docs/guide/intl/euro.html If you download and install the JDK documentation bundle, you will find this file at docs/guide/intl/euro.html. ======================================================================= DATA TRANSFER PROBLEMS ON WINDOWS ======================================================================= A bug in the data transfer API (4032895) prevents most objects from being copied to the Win32 clipboard. A common workaround is to convert objects to a String representation, since String objects are not affected by this bug. One popular technique for converting an object to a string is to write the object into a ByteArrayOutputStream and convert the stream to a String with toString(). String.getBytes() reverses the process. There is a potential problem with this kind of byte/character conversion. Both toString() and getBytes() rely on a locale-specific character encoder to translate byte values to and from Unicode character values. Not all encoders assume a one-to-one relationship between byte values and character values. To ensure a reliable translation, do not rely on the default locale encoder. Explicitly specify an encoder that uses a reversible translation, such as ISO8859_1. Do this by passing the encoder name to toString() and getBytes(): aString = aStream.toString("ISO8859_1"); aByteArray = aString.getBytes("ISO8859_1"); In releases prior to JDK 1.1.7, the need to use a reversible encoding was not apparent to most programmers. ISO8859_1 was the default encoder for western locales on both Solaris and Win32. A program's dependence on ISO8859_1 might not be apparent if the program was not tested under a non-western locale. ======================================================================= DEPLOYING JAVA APPLICATIONS ======================================================================= A Java application, unlike a Java applet, cannot rely on a web browser for installation and runtime services. When you deploy a Java application, your software bundle will probably consist of the following parts: * Your own class, resource, and data files. * A runtime environment. * An installation procedure or program. The first item, you already have, of course. The remainder of this section covers the other two items. ----------------------------------------------------------------------- RUNTIME ENVIRONMENT ----------------------------------------------------------------------- To run your application, a user needs a Java virtual machine, the Java platform core classes, and various support programs and files. This collection of software is known as a runtime environment. The JDK software serves as a runtime environment. However, you probably can't assume your users have the JDK software installed, and your JDK software license doesn't allow you to redistribute JDK software files. JavaSoft provides a free, redistributable runtime environment called the Java Runtime Environment. Versions of this are are available for all platforms that run the JDK software. The Java Runtime Environment is available for download at: http://java.sun.com/products/jdk/1.1/jre/ The Win32 versions comes with a built-in installation program suitable for end-users. Solaris versions require the developer to provide installation support. The Java Runtime Environment for Win32 is available both with and without international support. The non-international version is much smaller, but is suitable only for English-speaking users. JavaSoft is not the only supplier of runtime software for Java programs. If you use a third-party runtime, you should make sure it is fully compatible with the Java Runtime Environment. For information on third-party runtime environments, see: http://java.sun.com/cgi-bin/java-ports.cgi ----------------------------------------------------------------------- INSTALLATION ----------------------------------------------------------------------- The final step in the deployment process occurs when the software is installed on individual user system. Installation consists of copying software onto the user's system, then configuring the user's system to support that software. This step includes installing and configuring the runtime environment. If you use the Java Runtime Environment, you must make sure that your installation procedure never overwrites an existing installation, unless the existing Java Runtime Environment is an older version. The Win32 version of the Java Runtime Environment is distributed as a self-installing executable. A simple way to redistribute the Java Runtime Environment is to include this executable in your software bundle. You can then have your installation program run the executable, or simply instruct the user to install the Java Runtime Environment before installing the rest of your bundle. The Win32 installation program records program information in the Windows Registry. This registry information includes the software version, which you should compare with the Java Runtime Environment version in your software bundle. For more information, refer to the the Java Runtime Environment Notes for Developers at: http://java.sun.com/products/jdk/1.1/runtime.html A more sophisticated approach is to install the Java Runtime Environment on your own system, then copy the files you need into your own installation set. If you choose this approach, you must include all files described as "required" in the Java Runtime Environment README. The Java Runtime Environment software can only be redistributed if all "required" files are included. See the LICENSE file for specifics. If you use this approach, do not try to emulate the installation steps performed by the Java Runtime Environment installer. You might "break" an existing Java Runtime Environment installation by missing a new or undocumented installation step. Instead, you should include the Java Runtime Environment files in your own application directory. In effect, your application has its own "private" copy of the Java Runtime Environment. If your application uses the networking classes, it may not run reliably under Winsock 1.1. (See "Possible Problems with Winsock," under "Installing and Running the JDK Software," above.) If your networking application must support Windows 95, which comes with Winsock 1.1, you will want to include a Winsock 2.0 install in your installation procedure. (Windows NT 4.0 and Windows 98 come with Winsock 2.0.) To provide Winsock 2.0, you need the Microsoft Windows Sockets 2.0 Software Development Kit. This free software can be downloaded from the following addresses: http://www.microsoft.com/win32dev/netwrk/winsock2/ws295sdk.html http://www.microsoft.com/windows95/info/ws2.htm ftp://ftp.microsoft.com/bussys/WinSock/winsock2/ ----------------------------------------------------------------------- Developed by Sun Microsystems, Inc. 4150 Network Circle, Santa Clara, California, 95054, U.S.A. Copyright (c) 1997-2002 Sun Microsystems, Inc. All rights reserved.