Re: Can I install new JavaRuntime version on top of previous? Automatic
(CLASS)PATH change?
Roedy Green wrote:
On Thu, 18 Feb 2010 13:27:42 -0800, markspace <nospam@nowhere.com>
wrote, quoted or indirectly quoted someone who said :
Raymond Schanks wrote:
Can I install a new JRE on top of an existing JRE (in the same directory) on WinXP?
Or do I have to uninstall the old JRE first?
You don't normally have to uninstall an old JRE first. The second one
does not go "on top of" the previous, the installer knows to make a
second directory.
I don't recall whether the PATH is updated or not. I think not, mainly
because this can be a security risk and and administrator often want to
handle that separately.
see http://mindprod.com/jgloss/multiplejres.html
You can have several installed, but unless you have very good reason
to, don't, because you will trip over yourself.
For most people, you are best off to uninstall your old JDKs and JREs
before installing new ones.
Then there is no possibility of using a different JRE/JDK from the one
you intended.
Since this is essentially a programmer's forum, it is likely that "most"
people here should be aware of how to install multiple JDKs. However, the OP
asked about JREs, for which Roedy's advice makes perfect sense.
As someone who takes on various projects for clients, not to mention needing
to stay aware of how things work in different versions just for training, I
find it exceedingly useful to keep multiple Java versions around. For now,
unless I have a particular need, I keep the latest versions of JDK 5 and JDK 6.
I also tell my IDEs where they are so that different projects can use
different versions. For example, I'm working on a Windows Java project that
uses JDK 5 under Eclipse, and I study on my Linux box using Java 6 and NetBeans.
On my previous contract there was a significant amount of code still under
Java 1.4, developed under Windows but deployed on Solaris.
This is just one developer's typical scenario.
--
Lew