Is the name of a method inside or outside the glass box?

A good answer might be:

Outside---so it can be "seen" and used by .

class CheckingAccount
{
  . . . .
  private int    balance;

  void processCheck( int  amount  )
  {                          
    int charge;
    if ( balance < 100000 )
      charge = 15; 
    else
      charge = 0;
    balance =  balance -  amount  - charge  ;

    // change the local copy in "amount"
    amount = 0 ; 
  }
}

class CheckingTester
{
  CheckingAccount act;

  public static void main ( String[] args )
  {
    int check = 5000;
    act = new CheckingAccount( "123-345-99", 
        "Wanda Fish",  100000 );

    // prints "5000"
    System.out.println( "check:" + check );

     // call processCheck with the value 5000
    act.processCheck( check );             

    // prints "5000" --- "check" was not changed
    System.out.println( "check:" + check ); 

  }
}

Within the body of a method, a parameter can be used just like any variable. It can be used in arithmetic expressions, in assignment statements, and so on.

However, changes made to the parameter do not have any effect outside the method body. A parameter is a "local copy" of whatever value the caller passed into the method. Any changes made to it affect only this local copy. For example:

This subject will be further discussed in a future chapter. For now, regard a parameter as a "one-way message" that the caller uses to send values to the method.

QUESTION 8:

Say that the main() method in the example did this:

   act.processCheck( 7000 );              // call processCheck with the value 7000

   amount = 0 ;        // change the local copy in "amount"