gud-jdb-use-classpath

gud-jdb-use-classpath is a variable defined in `gud.el'.
Its value is

t

Documentation:
If non-nil, search for Java source files in classpath directories.
The list of directories to search is the value of `gud-jdb-classpath'.
The file pathname is obtained by converting the fully qualified
class information output by jdb to a relative pathname and appending
it to `gud-jdb-classpath' element by element until a match is found.

This method has a significant jdb startup time reduction advantage
since it does not require the scanning of all `gud-jdb-directories'
and parsing all Java files for class information.

Set to nil to use `gud-jdb-directories' to scan java sources for
class information on jdb startup (original method).

You can customize this variable.