Mfrhtyj

My references section sometimes shows a lot of whitespace between words that I would like to remove.

For example, in the following screenshot, I would like to remove the extra spaces within the text "Describing a link":

I know that I can use mbox (for example, mbox{Describing a link}), but I'd like to apply some option to avoid this globally.

Update: The main answer worked for url, but now I get the same issue when using href:

bibitem{Reference2} Some Name, href{mailto:testlongname@example.com}{testlongname@example.com}

Here is the full example document:

documentclass[12pt, a4paper, twocolumn]{article}



usepackage{xurl} % Added based on the initial answer

usepackage{hyperref}

hypersetup{colorlinks = true, urlcolor = blue, linkcolor = blue, citecolor = blue}



usepackage[super,comma,sort&compress]{natbib}



usepackage{abstract}

renewcommand{abstractnamefont}{normalfontbfseries}

renewcommand{abstracttextfont}{normalfontsmallitshape}



title{Test Article}

author{Test Author}



begin{document}



twocolumn[

  begin{@twocolumnfalse}

    maketitle

    begin{abstract}

noindent

Test abstract.

      newlinenewline

    end{abstract}

  end{@twocolumnfalse}

]



section{Section1}



Lorem ipsum dolor sit ametcite{Reference1}, consectetur adipiscing elit. Fusce maximus nisi ligula. Morbi laoreet ex ligula, vitae lobortis purus mattis vel. Vestibulum ante ipsum primis in faucibus orci luctus et ultrices posuere cubilia Curae; Donec ac metus ut turpis mollis placerat et nec enim. Duis tristique nibh maximus faucibus facilisis. Praesent in consequat leo. Maecenas condimentum ex rhoncus, elementum diam vel, malesuada ante. Fusce pulvinar, mauris pretium placerat venenatis, lectus ex tempus lacus, id suscipit libero lorem eu augue. Interdum et malesuada fames ac ante ipsum primis in faucibus.



section{Section2}



Lorem ipsum dolor sit amet, consectetur adipiscing elit. Fusce maximus nisi ligula. Morbi laoreet ex ligula, vitae lobortis purus mattis vel. Vestibulum ante ipsum primis in faucibus orci luctus et ultrices posuere cubilia Curae; Donec ac metus ut turpis mollis placerat et nec enim. Duis tristique nibh maximus faucibus facilisis. Praesent in consequat leo. Maecenas condimentum ex rhoncus, elementum diam vel, malesuada ante. Fusce pulvinar, mauris pretium placerat venenatis, lectus ex tempus lacus, id suscipit libero lorem eu augue. Interdum et malesuada fames ac ante ipsum primis in faucibus.



begin{thebibliography}{99}

bibitem{Reference1} Describing a link, url{https://example.com/this_is_a_really_long_link_that_wraps_many_lines}

bibitem{Reference2} Some Name, href{mailto:testlongname@example.com}{testlongname@example.com}

end{thebibliography}



end{document}

In your case you can simply add usepackage{xurl} in your preamble. Be sure to call xurl before package hyperref (if you omit that, hyperref itself calls package url with the result you got ...)!

With the following code

documentclass[12pt, a4paper, twocolumn]{article}



usepackage{xurl} % <===================================================

usepackage{hyperref}

hypersetup{colorlinks = true, urlcolor = blue, linkcolor = blue, citecolor = blue}



usepackage[super,comma,sort&compress]{natbib}



usepackage{abstract}

renewcommand{abstractnamefont}{normalfontbfseries}

renewcommand{abstracttextfont}{normalfontsmallitshape}



title{Test Article}

author{Test Author}



begin{document}



twocolumn[

  begin{@twocolumnfalse}

    maketitle

    begin{abstract}

noindent

Test abstract.

      newlinenewline

    end{abstract}

  end{@twocolumnfalse}

]



section{Section1}



Lorem ipsum dolor sit ametcite{Reference1}, consectetur adipiscing elit. Fusce maximus nisi ligula. Morbi laoreet ex ligula, vitae lobortis purus mattis vel. Vestibulum ante ipsum primis in faucibus orci luctus et ultrices posuere cubilia Curae; Donec ac metus ut turpis mollis placerat et nec enim. Duis tristique nibh maximus faucibus facilisis. Praesent in consequat leo. Maecenas condimentum ex rhoncus, elementum diam vel, malesuada ante. Fusce pulvinar, mauris pretium placerat venenatis, lectus ex tempus lacus, id suscipit libero lorem eu augue. Interdum et malesuada fames ac ante ipsum primis in faucibus.



section{Section2}



Lorem ipsum dolor sit amet, consectetur adipiscing elit. Fusce maximus nisi ligula. Morbi laoreet ex ligula, vitae lobortis purus mattis vel. Vestibulum ante ipsum primis in faucibus orci luctus et ultrices posuere cubilia Curae; Donec ac metus ut turpis mollis placerat et nec enim. Duis tristique nibh maximus faucibus facilisis. Praesent in consequat leo. Maecenas condimentum ex rhoncus, elementum diam vel, malesuada ante. Fusce pulvinar, mauris pretium placerat venenatis, lectus ex tempus lacus, id suscipit libero lorem eu augue. Interdum et malesuada fames ac ante ipsum primis in faucibus.



begin{thebibliography}{99}

bibitem{Reference1} Describing a link, url{https://example.com/this_is_a_really_long_link_that_wraps_many_lines}

end{thebibliography}



end{document}

you get the result: