The Berkeley DB Java class files are now packaged as jar files. In the 4.0 release, the CLASSPATH environment variable must change to include at least the db.jar file. It can optionally include the dbexamples.jar file if you want to run the examples. For example, on UNIX:

export CLASSPATH="/usr/local/BerkeleyDB.4.8/lib/db.jar:/usr/local/BerkeleyDB.4.8/lib/dbexamples.jar"

For example, on Windows:

set CLASSPATH="D:\db\build_windows\Release\db.jar;D:\db\build_windows\Release\dbexamples.jar"

For more information on Java configuration, please see Java configuration and Building the Java API.