question: public PrefixFileFilter ( String [ ] prefixes , IOCase caseSensitivity ) { if ( prefixes == null ) { throw new IllegalArgumentException ( "The array of prefixes must not be null" ) ; } this . prefixes = new String [ prefixes . length ] ; System . arraycopy ( prefixes , 0 , this . prefixes , 0 , prefixes . length ) ; this . caseSensitivity = caseSensitivity == null ? IOCase . SENSITIVE : caseSensitivity ; }
target:  Constructs a new Prefix file filter for any of an array of prefixes specifying case-sensitivity. <p> The array is not cloned, so could be changed after constructing the instance. This would be inadvisable however.