question: static void checkFlags ( int flags ) { int allowedFlags = READ_ONLY_FLAG_MASK | EMPTY_FLAG_MASK | COMPACT_FLAG_MASK | ORDERED_FLAG_MASK ; int flagsMask = ~ allowedFlags ; if ( ( flags & flagsMask ) > 0 ) { throw new SketchesArgumentException ( "Possible corruption: Invalid flags field: " + Integer . toBinaryString ( flags ) ) ; } }
target:  Checks just the flags field of the preamble