First char to upper case

Possible Duplicate:
How to upper case every first letter of word in a string?
Most efficient way to make the first character of a String lower case?

I want to convert the first letter of a string to upper case. I am attempting to use replaceFirst() as described in JavaDocs, but I have no idea what is meant by regular expression.

Here is the code I have tried so far:

public static String cap1stChar(String userIdea)
{
    String betterIdea, userIdeaUC;
    char char1;
    userIdeaUC = userIdea.toUpperCase();
    char1 = userIdeaUC.charAt(0);
    betterIdea = userIdea.replaceFirst(char1); 
    return betterIdea;
}//end cap1stChar

The compiler error is that the argument lists differ in lengths. I presume that is because the regex is missing, however I don't know what that is exactly.