double bass | Double (association football) | double | Double Dragon | body double | Double bass | double (baseball) | double agent | double feature | Mamee Double-Decker | Double Dare | the double | Pattern 1914 Enfield | double platinum | Double Dragon (TV series) | double-decker bus | Double (baseball) | Bombardier Double-deck Coach | The Double | RAF Locking | pattern matching | Pattern 1853 Enfield | NATO Double-Track Decision | Double Tenth Incident | Double-heading | double-headed eagle | Double-elimination tournament | Double Eagle II | Double Dutch Bus | Double Dee and Steinski |
This method uses double-checked locking, which should not be used prior to J2SE 5.0, as it is vulnerable to subtle bugs.