How to find whether an application is installed or not

Is there any way to find whether an application is installed or notand the path of the installed pathI got that with executing reg query from my java aplication but for thatreg tool should be installed ..Is there any way to get without that
[275 byte] By [Prakash_Halana] at [2007-11-26 18:26:05]
# 1
You can use an <installer-desc> to invoke a class that asks the user where it is, andif they do not know, or do not have it, it canbe installed at the time (assuming you can provide an installer, appropriate for their OS).
AndrewThompson64a at 2007-7-9 6:00:08 > top of Java-index,Desktop,Deploying...