In order to use tap4j with JUnit or TestNG you have to include tap4j-ext dependency in your project pom.xml. It will automatically add tap4j too, but you will have to include either JUnit or TestNG.
<dependency> <groupid>org.tap4j</groupid> <artifactid>tap4j-ext</artifactid> <version>4.4.2</version> </dependency>