Actually that 'void', is meant to be written as a value type that you want the output of. Generally, in a user created function, we ask to return a specific value of a certain type, and that value type is to be placed in place of 'void'.
'main' is just written to state that this is the main function of the program. It can be replaced by any word except for the reserved words.
'static' has to be typed if you want that function to be executed directly, i.e., in BlueJ, just by right clicking the class and selecting that function.