Hi all,

Well as you know characters such as '*' and '?' are reserved characters in regular expression so I suppose if I want to find the exact character (a '?' for example) in a string, I have to escape it with a backslash:

str=str.replaceAll("\?","a");

In the statement above, I need to replace all question marks with another character but it has a compile error:

Error(116,48): invalid escape character

to my surprise this code does the job while it should be interpreted as
one occurance of the '\' character or nothing at all:

str=str.replaceAll("\\?","a");


What's the problem? what's the general rule on escaping such characters?

Ya whenver u want to use the escape character in a regular expression u would have to necessarilly use "//" rather than using "/" . Since the later will not be recognised