After upgrading Jasper to the last version, it stopped finding one font: Symbol. The rest of the fonts seem to be fine. I have a bunch of ttfs in the same directory as where
Open jasperreports-x.x.x.jar, in my case jasperreports-3.7.2.jar.
Locate default.jasperreports.properties file and open it.
Find the line net.sf.jasperreports.awt.ignore.missing.font=false and change value from false to true net.sf.jasperreports.awt.ignore.missing.font=true.