program to take an optional argument that specifies the number of fish in the aquarium we could then invoke the program by typing the following in shell windowjava aquarium to specify that we want an aquarium with fish in it in this caseargs[ would refer to the string " one nice feature of the main method in class definition is that it allows each class to define stand-alone programand one of the uses for this method is to test all the other methods in class thusthorough use of the main method is an effective tool for debugging collections of java classes statement blocks and local variables the body of method is statement blockwhich is sequence of statements and declarations to be performed between the braces "{and "}method bodies and other statement blocks can themselves have statement blocks nested inside of them in addition to statements that perform some actionlike calling the method of some objectstatement blocks can contain declarations of local variables these variables are declared inside the statement bodyusually at the beginning (but between the braces "{and "}"local variables are similar to instance variablesbut they only exist while the statement block is being executed as soon as control flow exits out of that blockall local variables inside it can no longer be referenced local variable can either be base type (such as intfloatdoubleor reference to an instance of some class single statements and declarations in java are always terminated by semicolonthat isa ";there are two ways of declaring local variablestype nametype name initial_valuethe first declaration simply defines the identifiernameto be of the specified type the second declaration defines the identifierits typeand also initializes this variable to the specified value here are some examples of local variable declarationsdouble rpoint new point ( )point new point ( )