<dependency>
  <groupId>org.webjars.npm</groupId>
  <artifactId>popper.js</artifactId>
  <version>1.13.0</version>
</dependency>
<dependency>
    <groupId>org.webjars</groupId>
    <artifactId>webjars-locator</artifactId>
    <version>0.32-1</version>
</dependency>

<script th:src="@{/webjars/npm/popper.js/popper.min.js}" type="text/javascript"></script>

<script th:src="@{/webjars/popper.js/1.13.0/dist/popper.min.js}" type="text/javascript"></script>