question: public String lookupRelativeNativePath ( PathImpl path ) { String thisNative = getNativePath ( ) ; String pathNative = path . getNativePath ( ) ; if ( pathNative . startsWith ( thisNative ) ) { int i = thisNative . length ( ) ; while ( i < pathNative . length ( ) ) { if ( pathNative . charAt ( i ) != getFileSeparatorChar ( ) ) break ; i ++ ; } return i == pathNative . length ( ) ? "" : pathNative . substring ( i ) ; } else return pathNative ; }
target:  Returns a native path relative to this native path if the passed path is relative to this path, or an absolute path if the passed path is not relative to this path.