JAXBContext.newInstance( String contextPath ) javaodoc is missing the parameter and return type description:

public static JAXBContext newInstance​(String contextPath)
                               throws JAXBException
Create a new instance of a JAXBContext class.
This is a convenience method to invoke the newInstance(String,ClassLoader) method with the context class loader of the current thread.

Throws:
JAXBException - if an error was encountered while creating the JAXBContext such as
failure to locate either ObjectFactory.class or jaxb.index in the packages
an ambiguity among global elements contained in the contextPath
failure to locate a value for the context factory provider property
mixing schema derived packages from different providers on the same contextPath
packages are not open to java.xml.bind module