WADL2JAVA Mavaen Plugin Not generating the classes

Question

Using CXF WADL2JAVA Maven Plugin to generate the java rest client classes. But getting below error from cxf tool org.apache.cxf.tools.common.ToolException: java.lang.IllegalStateException: Single WADL resources element is expected

to replicate in you local. please create a simple maven project and use below given files into your project

pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>com.ndgroup.services</groupId>
  <artifactId>ndgroupjavaclient</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <packaging>jar</packaging>

  <name>ndgroupjavaclient</name>
  <url>http://maven.apache.org</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  
    <maven.compiler.source>1.6</maven.compiler.source>
    <maven.compiler.target>1.6</maven.compiler.target>

  </properties>

  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>3.8.1</version>
      <scope>test</scope>
    </dependency>
  </dependencies>
  <build>
  <pluginManagement>
        <plugins>
            <plugin>
                <groupId>org.apache.cxf</groupId>
                <artifactId>cxf-wadl2java-plugin</artifactId>
                <version>3.3.1</version>
                <executions>
                    <execution>
                        <id>generate-sources</id>
                        <phase>generate-sources</phase>
                        <configuration>
                            <sourceRoot>${project.basedir}/src/main/java</sourceRoot>
                            <wadlOptions>
                                <wadlOption>
                                    <wadl>${project.basedir}/src/main/resources/wadl/HoldRelease.wadl</wadl>
                                    <impl>true</impl>
                                     
                                    <packagename>com.nggroup.services</packagename>
                                </wadlOption>
                            </wadlOptions>
                        </configuration>
                        
                        <goals>
                            
                            <goal>wadl2java</goal>
                           
                        </goals>
                    </execution>
                </executions>
            </plugin>
      
        </plugins>
        </pluginManagement>
    </build>
</project>

HoldRelease.wadl

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<application xmlns="http://research.sun.com/wadl/2006/10">
    <doc xmlns:jersey="http://jersey.dev.java.net/" 
            jersey:generatedBy="Jersey: 1.0-ea-SNAPSHOT 10/02/2008 12:17 PM"/>
    <resources base="http://localhost:9998/storage/">
        <resource path="/containers">
            <method name="GET" id="getContainers">
                <response>
                    <representation mediaType="application/xml"/>
                </response>
            </method>
            <resource path="{container}">
                <param xmlns:xs="http://www.w3.org/2001/XMLSchema" 
                                    type="xs:string" style="template" name="container"/>
                <method name="PUT" id="putContainer">
                    <response>
                        <representation mediaType="application/xml"/>
                    </response>
                </method>
                <method name="DELETE" id="deleteContainer"/>
                <method name="GET" id="getContainer">
                    <request>
                        <param xmlns:xs="http://www.w3.org/2001/XMLSchema" 
                                                    type="xs:string" style="query" name="search"/>
                    </request>
                    <response>
                        <representation mediaType="application/xml"/>
                    </response>
                </method>
                <resource path="{item: .+}">
                    <param xmlns:xs="http://www.w3.org/2001/XMLSchema" 
                                            type="xs:string" style="template" name="item"/>
                    <method name="PUT" id="putItem">
                        <request>
                            <representation mediaType="*/*"/>
                        </request>
                        <response>
                            <representation mediaType="*/*"/>
                        </response>
                    </method>
                    <method name="DELETE" id="deleteItem"/>
                    <method name="GET" id="getItem">
                        <response>
                            <representation mediaType="*/*"/>
                        </response>
                    </method>
                </resource>
            </resource>
        </resource>
    </resources>
</application>

maven goal : clean install org.apache.cxf:cxf-wadl2java-plugin:wadl2java

Looking forward for your response