title: Execution failed for task ':genJaxb'. NPE
body: <p>I have a openjdk version &quot;1.8.0_292&quot;.</p>
  <p>I am trying to run the education <a href="https://github.com/spring-guides/gs-consuming-web-service" rel="nofollow noreferrer">project</a>.
  The project failed with following exeption:</p>
  <pre><code>Build file '/home/user/Desktop/gs-consuming-web-service/complete/build.gradle'line: 36
  
  Execution failed for task ':genJaxb'.
  &gt; java.lang.NullPointerException
  </code></pre>
  <p>Failed gradle task is:</p>
  <pre><code>project.ant {
          taskdef name: &quot;xjc&quot;, classname: &quot;com.sun.tools.xjc.XJCTask&quot;,
                  classpath: configurations.jaxb.asPath
          mkdir(dir: sourcesDir)
          mkdir(dir: classesDir)
  
              xjc(destdir: sourcesDir, schema: schema,
                      package: &quot;com.example.consumingwebservice.wsdl&quot;) {
  
  
                      arg(value: &quot;-wsdl&quot;) //NPE occurs in this line
  
  
                  produces(dir: sourcesDir, includes: &quot;**/*.java&quot;)
              }
  
              javac(destdir: classesDir, source: 1.8, target: 1.8, debug: true,
                      debugLevel: &quot;lines,vars,source&quot;,
                      classpath: configurations.jaxb.asPath) {
                  src(path: sourcesDir)
                  include(name: &quot;**/*.java&quot;)
                  include(name: &quot;*.java&quot;)
                  }
  
              copy(todir: classesDir) {
                      fileset(dir: sourcesDir, erroronmissingdir: false) {
                      exclude(name: &quot;**/*.java&quot;)
              }
          }
      }
  </code></pre>
  <p>The repository has similar <a href="https://github.com/spring-guides/gs-consuming-web-service/issues/54" rel="nofollow noreferrer">issue</a>.</p>
  <p>I am not good with Gradle and Groovy, but I want to improve it :)</p>
  <p>Could someone please advice me some practice on how to debug this issue?</p>