First of all, why do you want your research in java programming language? I will make the things unnecessarily harder. But you can use java. My advice is you to use Matlab to do your research. 

Dear Pratyu,

As so aptly Prof. Kamel you can use, but this is quite tedious implemented in Java programming language using object oriented technology. That is why I propose papers attached on the subject.

Best regards

Here are some alternative methods that you may consult:

Roberge, V., Tarbouchi, M., & Labonté, G. (2013). Comparison of parallel genetic algorithm and particle swarm optimization for real-time UAV path planning. IEEE Transactions on Industrial Informatics, 9(1), 132-141.

Wang, X., Yadav, V., & Balakrishnan, S. N. (2007). Cooperative UAV formation flying with obstacle/collision avoidance. IEEE Transactions on control systems technology, 15(4), 672-679.

Nikolos, I. K., Zografos, E. S., & Brintaki, A. N. (2007). UAV path planning using evolutionary algorithms. In Innovations in Intelligent Machines-1 (pp. 77-111). Springer Berlin Heidelberg.

Baker, J., Cunei, A., Flack, C., Pizlo, F., Prochazka, M., Vitek, J., ... & Holmes, D. (2006, April). A real-time java virtual machine for avionics-an experience report. In 12th IEEE Real-Time and Embedded Technology and Applications Symposium (RTAS'06) (pp. 384-396). IEEE.

Harder, R. W., Hill, R. R., & Moore, J. T. (2004). A Java™ universal vehicle router for routing unmanned aerial vehicles. International Transactions in Operational Research, 11(3), 259-275.

I hope that the contents are not too outdated, but the approach might provide you a better understanding and more references to your query (my 2 ¢).