//constructors
  CheckingAccount( String accNumber, String holder, int start )
  {
    accountNumber = accNumber ;
    accountHolder = holder ;
    balance       = start ;
  }
 
We have enough code to put together a test program. The test program will not do much, but it will compile and run.
class CheckingAccount
{
  // instance variables
  String accountNumber;
  String accountHolder;
  int    balance;
  //constructors
  CheckingAccount( String accNumber, String holder, int start )
  {
    accountNumber = accNumber ;
    accountHolder = holder ;
    balance       = start ;
  }
  // methods
}
class CheckingAccountTester
{
  public static void main( String[] args )
  {
    CheckingAccount account1 
            = new CheckingAccount( "123", "Bob", 100 );
    System.out.println( account1.accountNumber + " " +
        account1.accountHolder + " " + account1.balance );
  }
}
This program can be copied into NotePad, compiled, and run in the usual way. The output will be:
C:\chap32>java CheckingAccountTester 123 Bob 100