We downloaded the latest iDEAL module from the appstore. After filling in al the details (certificates, etc) I tried to update the issuers for test-mode. However, the module almost directly shuts down Mendix and throws this critical error: java.lang.NoClassDefFoundError: org/w3c/dom/Node at java.lang.Class.getDeclaredConstructors0(Native Method) at java.lang.Class.privateGetDeclaredConstructors(Class.java:2493) at java.lang.Class.getConstructors(Class.java:1517) ..... Caused by: java.lang.ClassNotFoundException: org.w3c.dom.Node not found by project  at org.apache.felix.framework.BundleWiringImpl.findClassOrResourceByDelegation(BundleWiringImpl.java:1532) at org.apache.felix.framework.BundleWiringImpl.access$400(BundleWiringImpl.java:75) at org.apache.felix.framework.BundleWiringImpl$BundleClassLoader.loadClass(BundleWiringImpl.java:1955) at java.lang.ClassLoader.loadClass(ClassLoader.java:358) Does anybody know why this error is occuring? And how to fix it? Thanks!
As Marcel figured out himself as well, the issue was a library conflict.
There can be many libraries that could be conflicting with each other, so far the two most common libraries i have seen that give an issue were:
You should be able to remove both libraries without any problems. If you are reviewing the libraries, always start with validating the libraries by name/version numbers. Having two different version of the same library could be another cause for this issue, if those versions have a significant difference.