(1) "throw": initiates an error routine (thru code, rather than by being caught); (2) (3) & (4) "switch"/"case"/"default": related keywords in a program flow construct; "switch" is the name of the construct and provides a variable; each "case" provides a possible value for the variable (if value of variable is the case's value, the code following that case executes); and "default" encompasses any value not already provided thru the cases. A "break" statement is normally used after the code of each case. However, there are exceptions where two or more cases would execute the same codes.

Thanks! what about "short, long, byte, float, char"

They are all different primary types. See this page of the java tutorials.