Checking Java Programs

It Usually Begins with javac

While you can't overlook the fact that the standard Java compiler javac from Sun includes a lot of error checking that is mandated by the Java language, you can easily miss the fact that it has a bunch of extra checking that is yours for the asking. Simply add the command-line option -Xlint and you will see a number of additional warnings. You can optionally append a comma-separated list of categories to this option, as shown in the "javac Xlint options" table—for example, -Xlint:deprecation,unchecked will run the standard compiler with extra details on use of deprecated code and unchecked type conversions.

javac -Xlint options

Option	Meaning
all	Enable all optional warnings; default if -Xlint appears alone on the javac command (Sun's documentation reads, "Enable all recommended warnings. In this release, all available warnings are recommended.")
none	Disable all optional warnings; default if -Xlint is not present on the javac command.
deprecation	Enable/disable warnings about deprecated code, code that is no longer a recommended part of the API.
unchecked	Enable/disable detailed warnings about unchecked type conversions.
fallthrough	Enable/disable warnings about case labels that should be preceded by break or other flow control but are not.
path	Enable/disable warnings about missing/unreadable CLASSPATH entries (my favorite!)
serial	Enable/disable warnings about missing "serial version unique identifiers" (discussed in the section "Enabling Useful Warnings" under Eclipse). ...