FREQUENTLY ASKED QUESTIONS Section 1: General Questions How much does BlueJ cost? BlueJ is, and will remain, free for all users. What's the licensing deal? Here it is: 1. Copyright, licensing and redistribution The BlueJ system and this tutorial are freely available to anyone for any kind of use. The system and its documentation may be redistributed freely. No part of the BlueJ system or its documentation may be sold for profit or included in a package that is sold for profit without written authorisation of the authors. The copyright © for BlueJ is held by M. Kölling and J. Rosenberg. 2. Will there be a version running on a Macintosh? BlueJ requires a Java 2 system to run on. Apple have announced that they will not support Java 2 on MacOS 9 and earlier systems, but that they will support Java 2 on MacOS X. So, as soon as MacOS X is released, we hope that we will get BlueJ up and running on the Mac again. 3. Can I get BlueJ via FTP? Yes, you can. The ftp server address is mars.pscit.monash.edu.au (anonymous login) and the path is /pub/mik/bluej/bluej-113.jar 4. What are the installation instructions again? Look at instructions.txt. 5. How can I stop the DOS window from opening when I start BlueJ? Windows users who don't want the DOS window opening on screen can set their system up to open the DOS window minimised. That way, it is still there to receive error output, but it does not get in the way. To do this you need to create a shortcut for BlueJ and edit the shortcut's properties. Detailed instructions are here. Section 2: Technical problems/Errors 1. When starting the installer, I get a message "command not found" or "Bad command or file name" or "The name specified is not recognzed as an internal or external command" If just typing "java" gives you an error such as "command not found" (but you know that Java is installed on your machine) then it is not in the command path. Add it to the path or use the full path name to start Java. You can use the full path name by typing something like C:\jdk1.3\bin\java -jar bluej-113.jar Note the the exact path depends on the location where you installed Java. 2. Error during installation: Cannot find the file "tools.jar". The default jdk1.2.2 installation gives you two java runtimes. One (called JRE) for end users (just execution), and another one (called JDK) for developers. For BlueJ, the developer version has to be used - only that version includes the "tools.jar" library. By default, the JRE version is executed - even if you change your environment PATH variable! (On Windows, JRE is, by default, installed in \Program Files\JavaSoft\JRE\.) There are two possible solutions: Uninstall jdk1.2.2. Then install again. When asked about which components to install, uncheck "JRE and Plug-in" (on the same screen where you are asked whether you want to install demos, sources, etc.) NOTE: you have to scroll down a bit to see this option! Start the installer with an absolute path: Eg. C:\jdk1.2.2\bin\java -jar bluej-113.jar Then, in the installer, where you are asked to enter the name of the Java executable, also enter the full path. Both of these should work (I hope). Exception in thread "main" java.util.zip.ZipException: No such file or directory This error indicates that the jar file (bluej-112.jar) is not found. Check whether this file exists, has the right name (some browsers add a ".zip" extension! Remove it!), and is in the right directory. Also check that you are in the same directory as the jar file, and check for spelling errors. 3. Error message: "Failed to load Main-Class manifest attribute ..." This typically happens when the jar file (bluej-112.jar) is not found. Check whether this file exists, has the right name (some browsers add a ".zip" extension! Remove it!), and is in the right directory. Also check that you are in the same directory as the jar file, and check for spelling errors. If that all fails, try an alternative that should also work: Instead of using the install command given in the original instructions (java -jar bluej-113.jar), use the following two commands: set CLASSPATH=bluej-113.jar java Installer 4. Error: Installer failed to open: Java.io.FileNotFoundException: Installer.class.tmp The installer writes some data to disk during installation. If you are getting this error, then the data could not be written. The reason may be that your file system is full (out of space), or that you are trying to install from non-writable media (such as a CD ROM).Move the installer to a writable file system with a bit of space. Error message: "Out of environment space". You have to increase the command shell's environment space. The best way to do this is as follows: Open the file config.sys (typically on C:\ ) in an editor (such as Notepad) and add the following line: shell=c:\windows\command.com /p /e:4096 Then restart your computer. In Windows systems that don't have a "config.sys" (eg. Windows ME), do the following: Open a DOS window. Find the "Properties" dialog, and then the "Memory" tab. Change the setting for "Initial Environment" to 4096. Click OK. You will have to close the DOS window and open a new one. From that new one, BlueJ should run. 5. Error message: "Exception in thread main: java.lang.NoClassDefFoundError: ..." This error message indicates that the main jar file (bluej.jar) was not found. This is typically caused by classpath problems. The most common cause on Windows systems is that BlueJ is installed in a directory path that contains spaces (eg in "Program Files"). These spaces (and possibly long file names) cause problems with Java's class path settings. Solution: Install bluej in a directory without spaces in the path (eg C:\bluej). 6. Error message: "Installer failed to open: Installer.class" This error most likely indicates that you double-clicked the jar file. The jar file cannot be installed by double-clicking. Please follow the installation instructions. Error: java.lang.ClassNotFoundException: ClassPathLoader There is currently a bug in BlueJ: it cannot cope with incorrect package lines. This error is usually caused by a class containing a "package ..." specification in its source, which is not the package it is currently in. Solution: remove the package line. 7. All menus greyed out Behaviour: all menus are greyed out, and nothing can be used because of it. Cause: you are using JDK 1.2.1. BlueJ requires JDK 1.2.2 or newer. Update JDK. 8. Error: "Failed to start debugger: java.net.SocketException: Option unsupported by protocol". The reason is most likely that you have a Windows system that was installed without support for TCP/IP. Solution: Reinstall Windows with TCP/IP enabled. (BlueJ uses sockets - and thus TCP/IP - for communication between processes.) 9. Error: "Too many parameters" / "Bad command or file name". Most likely, BlueJ or JDK was installed at a path that contains a space, for example C:\Program Files\bluej The path to JDK and BlueJ's home directory must not contain spaces. Solution: Install again at a location that has a path without spaces. 10. Can't find the answser to your here? If the answer to your question was not in the list, please mail a detailed description of your problem (including information about your system) to bluej-support@bluej.org