Which version of java should I use ?

I would like to know what the best version of java to use in order to get the best java experience.? I would also like to know if two versions ie 1.5 and 1.6 can run together on a machine ?

Unless your app requires a particular version, why not use the most recent, i.e. 1.7 (Icedtea) which is in fact the open source version.

Try to avoid running more than one version at a given time, because each will have its memory requirements and cannot share memory.

In general I’d recommend you use Java 1.6 for now. (but you don’t mention for what purpose you intend to use Java) And yes, you can have multiple JRE’s on a PC.

Will be used for viewing stock exchange graphs

I’d recommend java_1_6_0-sun unless you insist on running OSS. Some in the Java community have reported incompatibilities between the fully-open JDK and Sun’s 1.6 JRE. No doubt, those problems will be disappear in time, but for now, you’ll probably get the best end-user experience from Sun’s Java 6.

I’m guessing you mean you are viewing these graphs in an applet hosted in a browser (this isn’t an independent application you are running?).

Java 1.6 should be fine.