ORU-10027: buffer overflow

When running PLSQL with multiple DBMS_OUTPUT.PUT_LINE you may get:

ERROR at line 1:
ORA-20000: ORU-10027: buffer overflow, limit of 2000 bytes
ORA-06512: at "SYS.DBMS_OUTPUT", line 35
ORA-06512: at "SYS.DBMS_OUTPUT", line 161
ORA-06512: at "SYS.DBMS_OUTPUT", line 123
ORA-06512: at line 9

this is because default buffer is limited at 2000 bytes. This limit can be increased with

exec DBMS_OUTPUT.ENABLE(1000000);