java - Remove all empty lines

Question

I thought that wasn't that hard to do, but I want to remove all empty lines (or lines just containing blanks and tabs in Java) with String.replaceAll.

My regex looks like this:

s = s.replaceAll ("^[ |]*
$", "");

But it doesn't work.

I looked around, but only found regexes for removing empty lines without blanks or tabs.

question from:https://stackoverflow.com/questions/4123385/remove-all-empty-lines

Answer 1

Try this:

String text = "line 1

line 3


line 5";
String adjusted = text.replaceAll("(?m)^[ ]*
?
", "");
// ...

Note that the regex [ |] matches a space, a tab or a pipe char!

EDIT

B.t.w., the regex (?m)^s+$ would also do the trick.