If the solve method succeeded in finding a solution, you will then want to access that solution. The objective value of that solution can be queried using method:

double objval = cplex.getObjValue();

Similarly, solution values for all the variables in the array x can be queried by calling:

double[] xval = cplex.getValues(x);

More solution information can be queried from IloCplex, including slacks and, depending on the algorithm that was applied for solving the model, duals, reduced cost information, and basis information.