Oracle XE change password for System.

If Linux/Unix

export ORACLE_SID=XE
export ORACLE_HOME=[Oracle_XE_install_path]
sqlplus / as sysdba

SQL> alter user sys indentified by [new_password];

SQL> alter user system indentified by [new_password];

If windows

set ORACLE_SID=XE
set ORACLE_HOME=[Oracle_XE_install_path]
sqlplus / as sysdba

SQL> alter user sys indentified by [new_password];

SQL> alter user system indentified by [new_password];