How to know if the string variabel contains only space in java?

Question

I have a variable that\'s a string and I want to replace the string with \"null\" if the variable contains only a space or multiple spaces. How can I do it?

Answer 1

How about this?

if(yourstring.replace(" ","").length()==0) {
    yourstring = null;
}

Doesn't need regexes so should be a little more efficient than solutions that do.