I got the exact same error calling soap-webservices in java11.
I finally got it to work in my testproject by adding the following dependency to pom.xml
<dependency>
<groupId>com.sun.xml.ws</groupId>
<artifactId>rt</artifactId>
<version>2.3.1</version>
</dependency>
As my production environment is not converted to maven yet, I then found out that I needed these jar-files on the classpath:
jaxb-runtime-2.3.1.jar
jaxws-api-2.3.1.jar
javax.xml.soap-api-1.4.0.jar
rt-2.3.1.jar
streambuffer-1.5.3.jar
policy-2.7.5.jar
stax-ex-1.8.jar
javax.jws-api-1.1.jar
saaj-impl-1.5.0.jar
gmbal-api-only-3.1.0-b001.jar