csv - Removing space in Java error -

basically, program convert data .csv format. but, faced error such when open file in excel, displays data when in notepad, becomes characters ㈬㥙〳㈬㥙ㄳ㌬かㄹ㌬か㌹㌬ㅋㄳ㌬ㅋ㈳㌬ㅋ㌳㌬ㅋ㐳

here's line of code

string resultstring = stringwriter.tostring(); ( string cheese: pie.keyset() ) {     resultstring += system.getproperty("line.separator") + cheese + "," +      pie.get(cheese).tostring();      resultstring = resultstring.replaceall(",$" , "").replaceall(" ", ""); }  this.writetofile(resultstring); 

i have multiple file method remove space file has error. i've tried multiple methods such removing before first resultstring , @ of pie.get(cheese).tostring().

also tried .replace(" ", ""); , replaceall("\\s","")

the data contains special characters. these characters not rendered default encoding. when writing/creating text/csv file, set character encoding utf-8. can in java program itself.