tfm@tfm-desktop:~/Bluetooth$ export CLASSPATH="/home/tfm/avetanaBluetooth.jar"
tfm@tfm-desktop:~/Bluetooth$ javac HelloWorld.java
tfm@tfm-desktop:~/Bluetooth$ java HelloWorld
Exception in thread "main" java.lang.NoClassDefFoundError: HelloWorld
tfm@tfm-desktop:~/Bluetooth$ ls
HelloWorld.class  HelloWorld.java  Server.class  Server.java  Server.java~
tfm@tfm-desktop:~/Bluetooth$ export CLASSPATH=""
tfm@tfm-desktop:~/Bluetooth$ java HelloWorld
hello world
tfm@tfm-desktop:~/Bluetooth$