Failed during checkstyle configuration: unable to parse configuration stream

Question

I am currently working on implementing checkstyle for maven/java projects. As the project of my company is way to complex and way too big, i started off with a smaller project just to test if it works. Implementation was good so far. I set up my checkstyle.xml connected it to the pom.xml, all set up. Also in the reporting section, as i want some output afterwards. The problem is, that somehow it wants to parse something, but I don't even have access to those files.

CheckStyle.xml :

<!DOCTYPE module PUBLIC
  "-//Puppy Crawl//DTD Check Configuration 1.3//EN"
  "http://www.puppycrawl.com/dtds/configuration_1_3.dtd">
<module name="Checker">
    <module name="TreeWalker">
        <module name="AvoidStaticImport">
            <property name="excludes" 
value="java.lang.System.out,java.lang.Math.*" />
        </module>
    </module>
</module>
 <module name="ImportOrder">
   <property name="groups" value="*,javax,java"/>
   <property name="ordered" value="true"/>
   <property name="separated" value="false"/>
   <property name="option" value="top"/>
   <property name="sortStaticImportsAlphabetically" value="true"/>
</module>
<module name="SuppressionXpathSingleFilter">
    <property name="checks" value="ImportOrder"/>
    <property name="message" value="^'java\..*'.*"/>
</module>

pom.xml:

<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-checkstyle-plugin</artifactId>
            <version>3.1.0</version>
            <configuration>
                <configLocation>checkstyle.xml</configLocation>
            </configuration>
            <executions>
                <execution>
                    <goals>
                        <goal>check</goal>
                    </goals>
                </execution>
            </executions>
        </plugin>
    </plugins>
    </build>
    <reporting>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-checkstyle-plugin</artifactId>
                <version>3.1.0</version>
                <configuration>
                    <configLocation>checkstyle.xml</configLocation>
                </configuration>
            </plugin>
        </plugins>
    </reporting><!---->
<dependencies>
    <dependency>
        <groupId>org.apache.commons</groupId>
        <artifactId>commons-lang3</artifactId>
        <version>3.9</version>
    </dependency>
</dependencies>

Stack Trace:

[INFO] --- maven-checkstyle-plugin:3.1.0:check (default) @ testHelloWorld ---
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  3.464 s
[INFO] Finished at: 2019-07-17T11:34:20+02:00
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-checkstyle-plugin:3.1.0:check (default) on project testHelloWorld: Failed during checkstyle execution: Failed during checkstyle configuration: unable to parse configuration stream - The markup in the document following the root element must be well-formed.:11:3 -> [Help 1]
org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal org.apache.maven.plugins:maven-checkstyle-plugin:3.1.0:check (default) on project testHelloWorld: Failed during checkstyle execution

Caused by: org.apache.maven.plugin.MojoExecutionException: Failed during checkstyle execution

Caused by: org.apache.maven.plugins.checkstyle.exec.CheckstyleExecutorException: Failed during checkstyle configuration

Caused by: com.puppycrawl.tools.checkstyle.api.CheckstyleException: unable to parse configuration stream - The markup in the document following the root element must be well-formed.:11:3

As well as: Caused by: org.xml.sax.SAXParseException: The markup in the document following the root element must be well-formed.

I get the checkstyle-result.xml, but it's empty. Before I got an empty XML template back, so it worked, without any todos. I still expected a checkstyle.html file for the report.

Answer 1

Your checkstyle.xml is not well-formed. A well-formed XML document has a single root element. You should place your ImportOrder and SuppressionXpathSingleFilter modules under the TreeWalker like this:

<!DOCTYPE module PUBLIC
    "-//Puppy Crawl//DTD Check Configuration 1.3//EN"
    "http://www.puppycrawl.com/dtds/configuration_1_3.dtd">
<module name="Checker">
  <module name="TreeWalker">
    <module name="AvoidStaticImport">
      <property name="excludes" value="java.lang.System.out,java.lang.Math.*"/>
    </module>
    <module name="ImportOrder">
      <property name="groups" value="*,javax,java"/>
      <property name="ordered" value="true"/>
      <property name="separated" value="false"/>
      <property name="option" value="top"/>
      <property name="sortStaticImportsAlphabetically" value="true"/>
    </module>
    <module name="SuppressionXpathSingleFilter">
      <property name="checks" value="ImportOrder"/>
      <property name="message" value="^'java\..*'.*"/>
    </module>
  </module>
</module>