question: public final static boolean isJavaFileName ( String name ) { int nameLength = name == null ? 0 : name . length ( ) ; int suffixLength = SUFFIX_JAVA . length ; if ( nameLength < suffixLength ) return false ; for ( int i = 0 ; i < suffixLength ; i ++ ) { char c = name . charAt ( nameLength - i - 1 ) ; int suffixIndex = suffixLength - i - 1 ; if ( c != SUFFIX_java [ suffixIndex ] && c != SUFFIX_JAVA [ suffixIndex ] ) return false ; } return true ; }
target:  Returns true iff str.toLowerCase().endsWith(".java") implementation is not creating extra strings.