New to Java

I want to view only the first 5 characters of a string.
The string variable may be empty.

Here are the two ways I've tried to do this:
ctyCd is a string variable up to 25 characters long.
ONE:
if (ctyCd.equals(" "))
{
ctyCd = ctyCd.substring(0, 0);
}
else
{
ctyCd = ctyCd.substring(0, 5);
}

TWO:
if (ctyCd != null)
{
ctyCd = ctyCd.substring(0, 5);
}

Both ways reflect the same out of bound error:
java.lang.StringIndexOutOfBoundsException: String index out of range: 5

Thanks for any help.