when trying to make a diagram of the project i’m making using maven as a project management, and simple spring boot cassandra api rest example, cannot make the properly UML diagrams, and instead of MYECLIPSE says
org.eclipse.jdt.core.dom.SingleVariableDeclaration cannot be cast to org.eclipse.jdt.dom.BodyDeclaration
Sorry that you are seeing this issue. This looks like a code related limitation in one of your java files.
Can you please share with us the full stacktrace of the error from the Error Log view? Also share with us the project files to help us replicate the problem at our end. You can zip the project and attach it.
If you cannot share all the files, then please uncheck the java files one by one in the UML reverse engineering wizard and check which java file is causing the problem and share that file with us.
Also share with us the full log file from workspace dir/.metadata/.log to check if any related errors are logged.