Java string replace and the NUL NULL ASCII 0 character

Question

Testing out someone elses code  I noticed a few JSP pages printing funky non-ASCII characters  Taking a dip into the source I found this tidbit      remove any periods from first name e g  Mr  John -- gt  Mr John firstName   firstName trim   replace       0      Does replacing a character in a String with a null character even work in Java  I know that   0  will terminate a C-string  Would this be the culprit to the funky characters

User · Answer

Should be probably changed to   firstName   firstName trim   replaceAll

User · Answer

Does replacing a character in a String with a null character even work in Java  I know that   0  will terminate a c-string    That depends on how you define what is working  Does it replace all occurrences of the target character with   0   Absolutely   String s    food  replace  o     0    System out println s indexOf   0         1  System out println s indexOf  d         3  System out println s length         4  System out println s hashCode       f  31 31 31    d        true    Everything seems to work fine to me  indexOf can find it  it counts as part of the length  and its value for hash code calculation is 0  everything is as specified by the JLS API   It DOESN T work if you expect replacing a character with the null character would somehow remove that character from the string  Of course it doesn t work like that  A null character is still a character   String s   Character toString   0    System out println s length         1  assert s charAt 0     0    It also DOESN T work if you expect the null character to terminate a string  It s evident from the snippets above  but it s also clearly specified in JLS  10 9  An Array of Characters is Not a String       In the Java programming language  unlike C  an array of char is not a String  and neither a String nor an array of char is terminated by   u0000   the NUL character          Would this be the culprit to the funky characters    Now we re talking about an entirely different thing  i e  how the string is rendered on screen  Truth is  even  Hello world   will look funky if you use dingbats font  A unicode string may look funky in one locale but not the other  Even a properly rendered unicode string containing  say  Chinese characters  may still look funky to someone from  say  Greenland   That said  the null character probably will look funky regardless  usually it s not a character that you want to display  That said  since null character is not the string terminator  Java is more than capable of handling it one way or another     Now to address what we assume is the intended effect  i e  remove all period from a string  the simplest solution is to use the replace CharSequence  CharSequence  overload   System out println  A E I O U  replace               AEIOU   The replaceAll solution is mentioned here too  but that works with regular expression  which is why you need to escape the dot meta character  and is likely to be slower

User · Answer

Does replacing a character in a String   with a null character even work in   Java    No      Would this be the culprit to the funky characters    Quite likely

User · Answer

This does cause  funky characters    System out println   Mr  Foo  trim   replace       0       produces   Mr   Foo   in my Eclipse console  where the    is shown as a square box   As others have posted  use String replace

User · Answer

I think it should be the case  To erase the character  you should use replace          instead

[java] Java string replace and the NUL (NULL, ASCII 0) character?

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