You are calling the setSalary method on the class name not the object name.
There are several other design and style errors, e.g. capital letters missed out (which caused your error message), public fields.
You have made the salary member variable in class empstatic. That means that there is only one copy of the variable which is shared between all emp objects. In other words, all employees have the same salary, and if you call setSalary on one emp object, then it changes for all employees. Is that really what you meant to do?
Remove the static from the declaration of the variable salary in line 3.
Also, line 22 is wrong, you want to call setSalary on the object that you've just created, and not on the emp class.