do you think java will exist in the future?
if yes then how do you think?

yes!

Java has its shortcomings (performance is not good as C/C++, ) But it also has its advantages. It is much easier to
start with Java. It takes much longer time to train a non-C programmer to an intermediate C/C++ programmer than to train
a non-Java programmer to an intermediate Java programmer.
The software industry currently is in short of good programmers to improve productivity. Java fits this need.

Also Java programming model pretty much fits the internet
programming. I am pretty much sure that Java servlet programming will continue to be very hot because many websites upgrade their cgi with Java servlets. The emergence of many Java application server, such as Weblogic, Enhydra,
, seems to say that Java will exist, at least in the following decade.

However, it absolutely does not mean C/C++ will disappear from software industry. At least Operating Systems, Database Systems and critical web servers will be surely written by C. Many performance critical systems will continue to be written in C/C++.

Java fits some particular needs which lead to its existence and evolution.