Premise: Green Day is an American punk rock band formed in 1986 by lead vocalist and guitarist Billie Joe Armstrong and bassist Mike Dirnt . For much of the group 's career , the band has been a trio with drummer Tré Cool , who replaced former drummer John Kiffmeyer in 1990 prior to the recording of the band 's second studio album , Kerplunk ( 1991 ) . On April 18 , 2015 , the band was inducted into the Rock and Roll Hall of Fame as a part of the 2015 class in their first year of eligibility .
Hypothesis: Green Day is not a music group.
Label: CONTRADICTION