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FREQUENTLY ASKED QUESTIONS ABOUT JAVA and JDKTM |
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Last updated January 1997.
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 This collection of frequently asked questions (FAQ) provides brief answers to many common questions about the Sun JavaTM Platform, programming language, and the Java Development Kit (JDK). It also provides links to more detailed information available from this web site. Please check here for answers before posting a question to one of the Java-related newsgroups or before sending email to any of the addresses at JavaSoft e-mail addresses. A. Getting started with Java:
B. Getting information and staying in touch:
C. Java-enabled Netscape:
D. Marketing, licensing, and planning:
E. Troubleshooting: We try to make as much information as possible available through our Web site, http://java.sun.com/. If you have trouble finding the information you need there, please let us know.
 
A. Getting started with Java:
A1. What releases of Java are currently available? What do they contain? A1. What releases of Java are currently available? What do they contain? The Java programming language is currently shipping as a product known as the Java Development Kit. The final Java 1.0 release is JDK 1.0.2. The latest Java 1.1 release is located at the JDK 1.1.x download page Each release of the Java Development Kit (JDK) contains:
To run Java 1.0 applets, use Netscape Navigator 3.x or other browsers that support Java applets. To run Java 1.1 applets, use Hotjava 1.x or Netscape Navigator 4.x or other browsers that support the newest version of the Java API. For details, see: The JavaTM Development Kit (http://java.sun.com/products/jdk/) A2. What platforms is the JDK available on? The JDK 1.0.2 is available on these platforms:
The JDK 1.1.4 is available on these platforms:
A3. What about a version for my favorite platform XYZ? When can I get it? These are extremely popular questions, and important ones. What we can currently say is:
Amiga, Linux, NeXT, OS/2, Windows 3.1, Windows 32s, ...
We've provided our source code to make third-party
ports like these possible, but we are not officially overseeing
or tracking them. For more information, please check out:
Platforms Supporting Java (http://java.sun.com/cgi-bin/java-ports.cgi) A4. How do I download Java and/or JDK? How do I install it? You can get our releases either with a World Wide Web (WWW) browser or by anonymous ftp. For details, including installation instructions, visit: The JavaTM Development Kit (http://java.sun.com/products/jdk/)Choose the version of the JDK you want, and go from there. A5. Where can I find information about HotJava? The current version of HotJava is 1.1Beta1 and is available at HotJava. This page has links to an email address for comments and to HotJava known bugs. A6. How can I get started programming in Java? See our page which can guide you in the right direction: Getting Started with Java.A7. Do I need special server software to use applets? No. Java applets may be served by any HTTP server. On the server side they are handled the same as any other file, such as a text, image, or sound file. All the special action happens when the applet class files are interpreted on the client side by a Java-enabled browser, such as HotJava or 1.x or Netscape 3.x/4.x. See our "Who's Licensing Java?" page:
Who's Licensing Java? A9. Is JavaScript available? How do I find out more about it? The initial version of JavaScript is available in current releases of Netscape Navigator 3.x. For more information, including a pointer to the full press release, see the Netscape JavaScript page:
Netscape JavaScriptA10. What are the security problems I've heard about JavaScript scripts? JavaScript is a scripting language used with Netscape Navigator. There have been reports of privacy problems with JavaScript, and Netscape is committed to addressing those concerns. JavaScript cannot be used to invoke Java applets. The privacy problems reported with JavaScript are not present in Java applets. A11. I can't find the API documentation on any classes in the sun.* packages. Where is it? The short answer is that we provide documentation only for the public classes in java.*. We do not provide documentation for sun.* because those are the Sun-specific implementation, and specifically not part of the Java API standard, and are therefore subject to change without notice. In general, we don't provide javadoc documentation for sun.* classes in order to discourage developers from writing programs that use them. For further explanation, see the next question. However, if you must have it, the documentation for sun.* is available in the doc comments in the source code release available separately from the JDK, mentioned in question A12. For example, the doc comments for sun.net are in the source files located at: /src/share/sun/sun/net/*.javaThis source code release does not include javadoc-generated documentation. You would have to generate those docs yourself using javadoc. A12. Why developers should not write programs that call 'sun' packages JavaSoft supports into the future only classes in java.* packages, not sun.* packages. In general, API in sun.* is subject to change at any time without notice. For more details, see the article Why Developers Should Not Write Programs That Call 'sun' Packages. A13. Where can I get the Java source code? JavaSoft has two separate bundles of source code that you can obtain at no charge:
B. Getting information and staying in touch:
B1. Where did the Java name come from? What does it stand for? B1. Where did the Java name come from? What does it stand for? The name was chosen during one of several brainstorming sessions held by the Java team. We were aiming to come up with a name that evoked the essence of the technology -- liveliness, animation, speed, interactivity, and more. "Java" was chosen from among many, many suggestions. The name is not an acronym, but rather a reminder of that hot, aromatic stuff that many programmers like to drink lots of. B2. Can the Java team keep me informed of latest developments? We no longer keep a list of people to inform; when we started that, we never expected that so many people would be writing to us every day! If you'd like to keep informed, the best way is to visit our Web site
JavaSoft Home Page (http://java.sun.com/) periodically and participate in the Java-related newsgroups. Note in particular that our "What's New" page:
What's New at JavaSoft (http://java.sun.com/nav/new/) provides an overview of the most recent developments, press releases, and so on concerning Java. B3. What newsgroups carry information about Java? Several newsgroups are currently available, including:
comp.lang.java
comp.lang.java.advocacy
comp.lang.java.announce
comp.lang.java.api
comp.lang.java.beans
comp.lang.java.databases
comp.lang.java.gui
comp.lang.java.help
comp.lang.java.machine
comp.lang.java.misc
comp.lang.java.programmer
comp.lang.java.security
comp.lang.java.setup
comp.lang.java.softwaretools
comp.lang.java.tech
comp.lang.javascript
B4. What email addresses are available?
Information about our internal e-mail addresses is available at
JavaSoft e-mail addresses. B5. What documentation is available? In what formats? How can I get it? We provide a wide range of documentation (white papers, API specifications, programmer's guide, and more), reachable from our documentation page:
Documentation Index (http://java.sun.comnav/read/docindex.html) Most of our documents are available in HTML, PostScript and PDF formats. B6. Can you send me information by regular mail or by email? Sorry, but we're mainly set up to distribute information through our Web site (http://java.sun.com/) and ftp site (java.sun.com). We want to get as much information out and available as possible, but we can only handle the volume via these customer-initiated mechanisms. B7. Can I be an alpha or beta tester? Yes, that's essentially what you're doing when you use our beta release software and send in bug reports. We generally don't have separate formal programs for early-release testing. B8. Are Java programming courses available? Where? At what price? SunService is providing Java programming courses at sites around the world; see
Sun Educational Services (http://www.sun.com/sunservice/suned/) B9. How do I file bug reports or feature suggestions? See instructions on our bug report page:
Submitting a Bug or Feature Request We will not be able to acknowledge each report individually. Please accept our gratitude in advance -- your feedback is crucial to our work.
C. Java-enabled Netscape:
C1. Can all Netscape 3.x versions run Java applets? C1. Can all Netscape 3.x versions run Java applets? Netscape 3.x supports Java 1.0 applets on many but not all platforms. See the release notes for your platform at:
Netscape Navigator Release Notes Java-enabled versions of Netscape 3.x will only run beta and 1.0.2 applets, which can be written with the 1.0.2 Java Development Kit (JDK). Be aware that there are many Web pages with alpha applets, which Netscape 3.x will not handle. You can distinguish between alpha and beta applets by looking at the html source for a page: alpha applets use the <app> tag, whereas beta applets use the <applet> tag. Hotjava and Java-enabled versions of Netscape 4.x will run 1.1.x applets, which can be written in with JDK 1.1.x. C2. Can you help me with using Java in Netscape? For questions that specifically concern installation, troubleshooting, feature availability, and how to do something specific with applets in the Netscape browser, it's best to ask Netscape directly. For instance, to report Netscape bugs, you can use:
Netscape Bug Report
D. Marketing, licensing, and planning:
D1. Is Java free? Where can I get information on licensing? D1. Is Java free? Where can I get information on licensing? The Java Development Kit (JDK) is free to download and use for commercial programming, but not to re-distribute. We have guidelines on our web site for using and/or licensing Java technology; see
Licensing Information If you have further commercial or licensing questions, please contact our representatives at 1-800-JAVASOFT, for international callers, please dial +1 512 434-1591.
Sun does not authorize the use of the Java logo. For more information about this and other special developer logos, please see:
Java Trademark Guidelines D3. What are your plans for XXX functionality? Why haven't you done YYY? We welcome all input regarding Java -- we will read and consider it. We're keeping many more options in mind than appear in our current releases. However, because we are focusing on moving toward our next release, we have time to answer only a small number of such questions. For APIs in particular, see: Java API Overview D4. Can you comment on company ZZZ's plans for licensing and using Java? No, we need to let other companies speak for themselves. We can only refer you to official press releases. For pointers to recent press releases, see our "What's New" page:
What's New at JavaSoft D5. How can I invest in Java on the stock market? Java technology is a product of Sun Microsystems, Inc., which is traded on NASDAQ under the symbol SUNW.
E. Troubleshooting:
E1. Will Java work with DOS file name limitations (8.3)? E1. Will Java work with DOS file name limitations (8.3)? Java relies on files with longer names than the old DOS limits, so if you are running older (pre-Windows 95) versions of DOS, Java will not work. If you are running a version of DOS (such as the one that comes with Windows 95) that allows long file names, you should not have any problems. Note that older versions of WinZip do not support long file names, even if the installed version of DOS does. You can get a free upgrade of WinZip with support for long file names from their web site. E2. javac: Superclass java.applet.Applet of class HelloWorld not found. The examples in the programmer's guide have been updated to conform to the new applet API in our 1.0.2 Java Development Kit (JDK). "Superclass not found" error messages are typical if you try to compile Java 1.0 beta code with an alpha version of javac. The recommended fix is to download a copy of the JDK, and do all further development with that. Another potential source of this error message is incorrect capitalization of either the file name or the class name in in the file. The Java system is case-sensitive, so a HelloWorld class is different from a helloWorld class, and so on. The appletviewer looks for a .hotjava directory inside your home directory to determine whether you are starting it for the first time. If the directory is not found, the appletviewer will pop up the copyright notice. The workaround is to manually create the .hotjava directory in your home directory. The following paragraphs explain how to do this. The appletviewer is written to recognize three MS-DOS environment variables for the location of a user home directory: it uses either HOME or the combination of HOMEDRIVE and HOMEPATH. Under Windows NT3.51, the HOMEDRIVE and HOMEPATH environment variables are set automatically. Under Windows 95, you will need to set the HOME environment variable to point to an existing directory. Once your home directory is set, all you need to do for Windows NT3.51 is to create the .hotjava directory inside of it:
mkdir %HOMEDRIVE%%HOMEPATH%\.hotjava
In Windows 95, the easiest method is to edit the AUTOEXEC.BAT file, adding the following line:
set HOME=C:\
Then save the file and reboot, so that the change to take effect. Once your computer has rebooted, open a DOS window and execute the following command:
mkdir %HOME%.hotjava
E4. My virus-checker program claims to have found a virus in some of the JDK files. What's going on? Although your virus checker may have discovered a real virus, you should consider the possibility that a false detection has occurred. Virus-checker programs can mistakenly find "viruses" in parts of the JDK where there really is no virus. This can happen when the virus checker detects a bit pattern in a class file that, by chance, matches a bit pattern in a virus. The types of viruses that can infect .exe or .com files typically cannot infect class files or jar files.
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