question: private void readUidListHeader ( String line ) throws IOException { if ( line == null ) throw new IOException ( "Header entry in uid-file is null" ) ; int gap1 = line . indexOf ( " " ) ; if ( gap1 == - 1 ) { throw new IOException ( "Corrupted header entry in uid-file" ) ; } int version = Integer . valueOf ( line . substring ( 0 , gap1 ) ) ; if ( version != 1 ) throw new IOException ( "Cannot read uidlists with versions other than 1." ) ; int gap2 = line . indexOf ( " " , gap1 + 1 ) ; lastUid = Optional . of ( MessageUid . of ( Long . valueOf ( line . substring ( gap1 + 1 , gap2 ) ) ) ) ; messageCount = Integer . valueOf ( line . substring ( gap2 + 1 , line . length ( ) ) ) ; }
target:  Parses the header line in uid list files. The format is: version lastUid messageCount (e.g. 1 615 273)