WebService Client Tester is not Working on GlassFish Server

If you are writing a SOAP Webservice, then you may face the following situation:

WSDL: (/YourProject/YourService?wsdl) is working fine but 
Tester (/YourProject/YourService?Tester) is not working 

Then, this can be solved using:
Create a new text file and rename it jaxp.properties (if it doesn't exist under /path/to/jdk1.8.0/jre/lib) and then write this line in it: javax.xml.accessExternalSchema = all

Then, restart the glassfish server and you are good to go! Good Luck.

There is another way to fix this if you are facing this problem when working on a Maven Web Project:

(Since the above solution perfectly worked for me, I didn't test this solution:)

If you are using the jaxws Maven plugin and you get the same error message, add the mentioned property to the plugin configuration:

...

<plugin>

  <groupId>org.jvnet.jax-ws-commons</groupId>

  <artifactId>jaxws-maven-plugin</artifactId>

  <version>2.3</version>

  <configuration>

    <!-- Needed with JAXP 1.5 -->

    <vmArgs>

        <vmArg>-Djavax.xml.accessExternalSchema=all</vmArg>

    </vmArgs>

  </configuration>

</plugin>

I found the above plugin configuration on StackOverflow.