On my Mac, it comes with several versions of Java installed, one of which is the default version. So I know that it is possible to have more than one version of Java installed on a Mac. I'm sure a PC should be able to do that too.
Joined: Dec 22, 2007
HI , I was installing BlueJ development tool. At the end of installation processit was giving the error.
It's perfectly possible to install different versions of Java on the same system, so that should not be an error. I have Java 5 and 6 installed on my computer.
Maybe you have to configure BlueJ to tell it which version of Java to use. Maybe it wasn't an error at all, but just a warning to remind you that you have to watch out which Java version is being used. I don't know BlueJ, so I can't really answer that question.
I think that particular message is normal behaviour for BlueJ, although I haven't seen it for a long time. I have vague memories of seeing it over 3 years ago when I started using BlueJ, so I might be mistaken. I seem to remember it is follow by a dialogue box asking one to choose which version of Java to use.
My opinion of BlueJ is that it does way too much "hand-holding". For example, when I first tried it, I knew a little bit about Java. I knew that it was good to always put a package declaration at the beginning of every Java source file. This was one of many problems that BlueJ caused me. BlueJ would not let me type in Java source code myself. I had to go to a pull-down menu in BlueJ and have it type the package declaration in form me.
BlueJ is meant for people who know absolutely nothing about Java and much of what you do in BlueJ is not learning Java, but learning the BlueJ IDE. This is also true of other IDEs. In my opinion, you should first learn Java from the command line -- that is using no IDE, and then use a real-world IDE like Eclipse that is actually used in the workplace.
If you're taking a beginning Java programming class that requires the use of BlueJ, look for things in the UI and notice what BlueJ does in the source code. The thing to remember is the Java source code. At some point, a professional Java developer would graduate from BlueJ into a professional IDE (such as Eclipse). [ January 07, 2008: Message edited by: Kaydell Leavitt ]
Joined: Oct 13, 2005
Agree with Kaydell Leavitt. I had no end of problems when I started with BlueJ; I had to graduate from BlueJ to command line to JCreatorLE (which I used as a glorified text editor) and then to Eclipse and NetBeans.