Line breaking of URLs in bibliographies

try it this way: (without \usepackage[hyphenbreaks]{breakurl})

\begingroup
\raggedright
\sloppy
\printbibliography
\endgroup

or without \raggedright:

The first URL has a large unbreakable section (runanywhere1) which must either form the end of the second or the beginning of the third line (given the specific font size, margin etc. of the example) if one insists on justified text. An acceptable (?) solution may be obtained by adding e.g. \sloppy or \emergencystretch 1.5em before \printbibliography.