Java™ Application Development on Linux - Dator

184Chapter 7The GNU Compiler for Java (gcj)7.4.2 Compiling a Multiclass ProgramFor contrast, Example 7.2 shows compiling a multiclass program that iscontained in a package (it is the Payback debt/savings/purchase calculator). 12Example 7.2 Compiling and running a multiclass program$ cd payback/src$ gcj -o payback -I. --main=net.multitool.Payback.Payback \net/multitool/Payback/Payback.java$ ./paybackPayback -- A savings/credit comparison toolCopyright (C) 2003 by Carl Albing and Michael SchwarzReleased under the GNU/GPL. Free Software..........etc.The -I switch names a directory that is to be prepended to the classpath.In this case, we added “.” which is the source directory for the Paybackprogram. 13 Notice the package elements expressed with dots for the --mainargument, and with slashes for the filename argument.NOTEThe gcj compiler does pick up and use the CLASSPATH environment variableif it is specified. Also, gcj has a number of switches besides -I for classpathmanipulation. We won’t cover those here; -I is the preferred method (accordingto the gcj manpage at any rate).12. Since this chapter was written, XML features were added to Payback that make it no longerwork with gcj.13. The Payback code can be found at the book’s Web site: http://www.javalinuxbook.com/.