jersey 2 restful custom application null pointer exception

Question

Hello I am new and I want to create an webservice on jersey 2.x with customized application sub-class but i alway got a weird null-exception when i load my webservice Here my service class

 package org.depplus.ws;
    import javax.ws.rs.GET;
    import javax.ws.rs.Path;
    import javax.ws.rs.Produces;
    import javax.ws.rs.core.MediaType;

    @Path("/HelloWorld")
    public class HelloWorld {
        @GET
        @Produces(MediaType.TEXT_PLAIN)
        public String sayPlainTextHello() {
            return "Hello Jersey";
        }

        @GET
        @Produces(MediaType.TEXT_HTML)
        public String sayHtmlHello() {
            return "<html> " + "<title>" + "Hello Jersey" + "</title>"
                + "<body><h1>" + "Hello Jersey" + "</body></h1>" + "</html> ";
        }

        @GET
        @Produces(MediaType.TEXT_HTML)
        @Path("/Hello2")
            public String sayHtmlHello2() {
            return "<html> " + "<title>" + "Hello 22222222" + "</title>"
            + "<body><h1>" + "Hello Jersey" + "</body></h1>" + "</html> ";
        }
    }

web.xml:

<web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
        metadata-complete="false">
        <display-name>Restful Web Application</display-name>

        <servlet>
            <servlet-name>org.depplus.ws.MyApplication</servlet-name>
        </servlet>
        <servlet-mapping>
            <servlet-name>org.depplus.ws.MyApplication</servlet-name>
            <url-pattern>/rest/*</url-pattern>
        </servlet-mapping>

    </web-app>

MyApplication.java:

package org.depplus.ws;
    import java.util.HashSet;
    import java.util.Set;


    public class MyApplication extends javax.ws.rs.core.Application {
        @Override
           public Set<Class<?>> getClasses() {
              Set<Class<?>> s = new HashSet<Class<?>>();
              s.add(HelloWorld.class);
              return s;
        }

    }

And exception when i run "localhost:8080/services/rest/HelloWorld" (tomcat)

java.lang.NullPointerException
sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
java.lang.ClassLoader.loadClass(ClassLoader.java:358)
org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1629)
org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1559)
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:461)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1023)
org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
java.lang.Thread.run(Thread.java:745)

Any ideal why it happen ?

EDIT1: Maven dependance:

<dependencies>
        <dependency>
            <groupId>org.postgresql</groupId>
            <artifactId>postgresql</artifactId>
            <version>9.2-1003-jdbc4</version>
        </dependency>     
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>3.0.1</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>org.glassfish.jersey.containers</groupId>
            <artifactId>jersey-container-servlet</artifactId>
            <version>2.13</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.6</version>
        </dependency>
        <dependency>
            <groupId>com.google.code.gson</groupId>
            <artifactId>gson</artifactId>
            <version>2.3</version>
        </dependency>

    </dependencies>

EDIT2: worked web.xml version: (work after some cleanup in tomcat server )

<web-app metadata-complete="false" version="3.0"
 xmlns="http://java.sun.com/xml/ns/javaee"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">
 <display-name>Restful Web Application</display-name>
 <!-- <servlet>
        <servlet-name>org.depplus.ws.MyApplication</servlet-name>
    </servlet>
    <servlet-mapping>
        <servlet-name>org.depplus.ws.MyApplication</servlet-name>
        <url-pattern>/rest/*</url-pattern>
    </servlet-mapping> -->
 <servlet>
  <servlet-name>services</servlet-name>
  <servlet-class>org.glassfish.jersey.servlet.ServletContainer</servlet-class>
  <init-param>
   <param-name>jersey.config.server.provider.packages</param-name>
   <param-value>org.depplus.ws</param-value>
  </init-param>
  <load-on-startup>1</load-on-startup>
 </servlet>
 <servlet-mapping>
  <servlet-name>services</servlet-name>
  <url-pattern>/rest/*</url-pattern>
 </servlet-mapping>
 <welcome-file-list>
  <welcome-file>/index.html</welcome-file>
 </welcome-file-list>
</web-app>

The init-param element tells Jersey which of your packages to search for Java files with web service annotations — VedantK, Nov 11 '14 at 06:13

score 0 · Accepted Answer · edited Mar 06 '17 at 22:22

0

Servlet tag must have ,

Servlet Name
Servlet Class
Init parameters (optional)

Something like this: XML FILE

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
          http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
    version="3.0">
    <display-name>Restful Web Application</display-name>

    <servlet>
        <servlet-name>jersey-serlvet</servlet-name>
        <servlet-class>
                     com.sun.jersey.spi.container.servlet.ServletContainer
                </servlet-class>
        <init-param>
             <param-name>com.sun.jersey.config.property.packages</param-name>
             <param-value>com.stack.overflow</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>jersey-serlvet</servlet-name>
        <url-pattern>/rest/*</url-pattern>
    </servlet-mapping>

</web-app>

I have executed your code its running fine with this XML file. You try it.

edited Mar 06 '17 at 22:22

Community

1
1

answered Nov 11 '14 at 05:30

VedantK

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according to here https://jersey.java.net/documentation/latest/deployment.html#deployment.servlet.2 part 4.7.2 it is not, im trying to work with servlet 3.0 – Minh Quang Nov 11 '14 at 05:31
Yes you are right ,Thanks for giving me this knowledge – VedantK Nov 11 '14 at 05:34
When i run with your xml file its not treating it as WebService as it not getting any root Resource class.You can check your console. – VedantK Nov 11 '14 at 06:00
your xml is based on jersey 1.x but i'm implementing jersey 2.x. should i go back to 1.x ? – Minh Quang Nov 11 '14 at 06:05
See if you get answer here – VedantK Nov 11 '14 at 06:14
http://stackoverflow.com/questions/18595016/deployment-of-a-jax-rs-application-using-web-xml-servlet-3-0-and-jersey – VedantK Nov 11 '14 at 06:15
after some thought i will change my application as your description here, custom application sub-class is too hard i guess – Minh Quang Nov 11 '14 at 06:55

jersey 2 restful custom application null pointer exception

1 Answers1