Multiple indexes for same column

SQL>CREATE TABLE t3
  (col1 NUMBER, col2 NUMBER);

TABLE created.

SQL>CREATE INDEX in_t3 ON t3(col1);

INDEX created.

SQL>CREATE INDEX in_t3_02 ON t3(col1);

CREATE INDEX in_t3_02 ON t3(col1)
  * ERROR at line 1: ORA-01408: such column list already indexed
 
    SQL> CREATE bitmap INDEX in_t3_02 ON t3(col1)invisible;
   
INDEX created.

—  Mohan G