title: java.lang.AbstractMethodError: javax.ws.rs.core.UriBuilder.uri(Ljava/lang/String;)Ljavax/ws/rs/core/UriBuilder
body: <p>I have downloaded Jersey Java Rest Api example from
  <a href="https://www.logicbig.com/tutorials/java-ee-tutorial/jax-rs/post-example.html" rel="nofollow noreferrer">https://www.logicbig.com/tutorials/java-ee-tutorial/jax-rs/post-example.html</a></p>
  <p>When I run this project using 'Run on server', it is accepting the following Rest api commands from Postman and perfectly working fine:</p>
  <pre><code>GET http://localhost:9900/jaxrs-post-example/rest/customers
  
  POST http://localhost:9900/jaxrs-post-example/rest/customers
  {
    &quot;firstName&quot;:&quot;David&quot;,
    &quot;lastName&quot;:&quot;Parker&quot;,
    &quot;school&quot;:&quot;CSI&quot;,
    &quot;standard&quot;:&quot;4&quot;,
    &quot;rollNumber&quot;:85
  }
  </code></pre>
  <p>When I send same command from ReactJS, the server is showing the following error.</p>
  <pre class="lang-java prettyprint-override"><code>SEVERE: Servlet.service() for servlet [jersey-json-example-serlvet] in context with path [/JAXRS-JSON] threw exception [Servlet execution threw an exception] with root cause
  java.lang.AbstractMethodError: javax.ws.rs.core.UriBuilder.uri(Ljava/lang/String;)Ljavax/ws/rs/core/UriBuilder;
      at javax.ws.rs.core.UriBuilder.fromUri(UriBuilder.java:119)
  </code></pre>
  <p>The code what is used in ReactJS is:</p>
  <pre class="lang-js prettyprint-override"><code>const projectParameters = {
    &quot;id&quot;:&quot;2152&quot;,
    &quot;name&quot;:&quot;David&quot;,
    &quot;address&quot;:&quot;12,new street&quot;,
    &quot;phoneNumber&quot;:&quot;8765489011&quot;           
  };
  
  const requestOptions = {
    method: 'POST',
    headers: { 'Accept': 'application/json','Content-Type': 'application/json' },
    body: JSON.stringify(projectParameters)
  };
  
  fetch('http://localhost:9900/JAXRS-JSON/rest/student/data/post',
              requestOptions)
              .then(response =&gt; response.json())
              .then(response =&gt; {                        
                  console.log(response);               
              });
  }
  
  </code></pre>
  <p>Questions:</p>
  <ol>
  <li><p>Is it related to CORS?</p>
  </li>
  <li><p>Please provide solution for this issue.</p>
  </li>
  </ol>