This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
I am guessing that Arun wants to run two different versions of Java (e.g. Java 1.4.2 and Java 5). This would be done by setting the PATH variable suitably, or by hard-coding the path to the java.exe file.