Junos 2300 Recovery Mode

Hit [Enter] to boot immediately, or space bar for command prompt.

ok boot -s
Enter full pathname of shell or 'recovery' for root password recovery or RETURN for /bin/sh: recovery

root@SURAKARTA> configure
Entering configuration mode
The configuration has been changed but not committed

[edit]
root@SURAKARTA# set system root-authentication plain-text-password
New password:
Retype new password:

[edit]
root@SURAKARTA# commit
commit complete

[edit]
root@SURAKARTA#
root@SURAKARTA# exit
Exiting configuration mode
root@SURAKARTA> quit

Reboot the system? [y/n]y


http://www.juniper.net/techpubs/software/junos/junos81/jweb81-user-guide/jN23F2A.html