ContributionsMost RecentMost LikesSolutionsRe: SoapUI doesn't start because of java.lang.NoClassDefFoundError: sun/misc/BASE64Decoder Prerequisite Make sure that you have Java (JRE) installed on your system nothing else... Re: SoapUI doesn't start because of java.lang.NoClassDefFoundError: sun/misc/BASE64Decoder It is a fresh install(unzip) of SoapUI-5.5.0-linux-bin.tar.gz launched with OpenJDK11 SoapUI doesn't start because of java.lang.NoClassDefFoundError: sun/misc/BASE64Decoder SoapUI 5.5.0 doesn't even start because of java.lang.NoClassDefFoundError: sun/misc/BASE64Decoder using jdk11 BUG with java10 (java9), sun.misc.BASE64Decoder not available anymore in java10(java9)wasremoved formerly deprecated classsun.misc.BASE64Decoder which is widely used, so soapui (including most recent v5.4.0) will not even start. Classjava.util.Base64should be used instead.