synchronized void clear(){
  maps=new Maps();
  tombstones.clear();
  ramBytesUsedCurrent.set(0);
  if (mgr != null) {
    mgr.removeListener(this);
    mgr=null;
  }
}

synchronized void clear ( ) { maps = new Maps ( ) ; tombstones . clear ( ) ; ramBytesUsedCurrent . set ( 0 ) ; if ( mgr != null ) { mgr . removeListener ( this ) ; mgr = null ; } }
called when this index is closed .
