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How do increase the number of nested if else statements allowed by maven

I have written my code to search if a node can be reached in a graph using java. I don't to change my code. I am using maven. When I try to compile it's giving me the error below.
[INFO] There is 1 error reported by Checkstyle 8.29 with com/github/ngeor/checkstyle.xml ruleset.
[ERROR] src/main/java/dsa/graphs/Graph.java:[160,25] (coding) NestedIfDepth: Nested if-else depth is 2 (max allowed is 1).
How do I get around this. I don't want to disable checkstyle at the same time I don't want to change my code. How can I increase that number to be more than 1.

I am presuming that you have the checkstyle under com.github.ngeor package so just go to the file and change/add
<module name="NestedIfDepth">
<property name="max" value="{AS_MUCH_AS_YOU_WANT}"/>
</module>
Or if you are referencing a checkstyle that is not under your control you can also override it.
Add the checkstyle plugin to your pom:
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-checkstyle-plugin</artifactId>
<version>3.1.1</version>
<configuration>
<configLocation>checkstyle.xml</configLocation>
<suppressionsLocation>checkstyle-suppressions.xml</suppressionsLocation>
<suppressionsFileExpression>checkstyle.suppressions.file</suppressionsFileExpression>
</configuration>
</plugin>
</plugins>
And of course you need to create checkstyle-surpressions.xml file:
<?xml version="1.0"?>
<!DOCTYPE suppressions PUBLIC
"-//Checkstyle//DTD SuppressionFilter Configuration 1.0//EN"
"https://checkstyle.org/dtds/suppressions_1_0.dtd">
<suppressions>
<suppress checks="NestedIfDepth"
files="Graph.java"
lines="{what_Lines_you_need}"/>
</suppressions>
This will

How can I determine the phases for a specific packaging type

In Maven, when I use <packaging>jar</packaging>, I can see the default phases defined in
~/.m2/repository/org/apache/maven/maven-core/3.0.3/maven-core-3.0.3.jar/META-INF/plexus/components.xml
But when I use <packaging>kar</packaging> to build Apache Karaf project, how can I know the phases for package type of kar, which is not defined in components.xml?

This is defined inside the karaf-maven-plugin. This plugin declares its own components.xml.
Taking the code from GitHub, this is the lifecycle of the kar packaging:
<component>
<role>org.apache.maven.lifecycle.mapping.LifecycleMapping</role>
<role-hint>kar</role-hint>
<implementation>org.apache.maven.lifecycle.mapping.DefaultLifecycleMapping</implementation>
<configuration>
<lifecycles>
<lifecycle>
<id>default</id>
<phases>
<process-resources>
org.apache.maven.plugins:maven-resources-plugin:resources
</process-resources>
<compile>
org.apache.karaf.tooling:karaf-maven-plugin:features-generate-descriptor
</compile>
<package>
org.apache.karaf.tooling:karaf-maven-plugin:kar
</package>
<install>
org.apache.maven.plugins:maven-install-plugin:install
</install>
<deploy>
org.apache.maven.plugins:maven-deploy-plugin:deploy
</deploy>
</phases>
</lifecycle>
</lifecycles>
</configuration>
</component>
So this invokes:
process-resources with org.apache.maven.plugins:maven-resources-plugin:resources
compile with org.apache.karaf.tooling:karaf-maven-plugin:features-generate-descriptor
package with org.apache.karaf.tooling:karaf-maven-plugin:kar
install with org.apache.maven.plugins:maven-install-plugin:install
deploy with org.apache.maven.plugins:maven-deploy-plugin:deploy
If you want to take a look at it inside your m2 repo, you should look inside (supposing you're using version 4.0.3)
~/.m2/repository/org/apache/karaf/tooling/4.0.3/karaf-maven-plugin-4.0.3.jar/META-INF/plexus/components.xml

Take a look at the META-INF/plexus/components.xml in the karaf-maven-plugin.jar.
<component>
<role>org.apache.maven.lifecycle.mapping.LifecycleMapping</role>
<role-hint>kar</role-hint>
<implementation>org.apache.maven.lifecycle.mapping.DefaultLifecycleMapping</implementation>
<configuration>
<lifecycles>
<lifecycle>
<id>default</id>
<phases>
<process-resources>
org.apache.maven.plugins:maven-resources-plugin:resources
</process-resources>
<compile>
org.apache.karaf.tooling:karaf-maven-plugin:features-generate-descriptor
</compile>
<package>
org.apache.karaf.tooling:karaf-maven-plugin:kar
</package>
<install>
org.apache.maven.plugins:maven-install-plugin:install
</install>
<deploy>
org.apache.maven.plugins:maven-deploy-plugin:deploy
</deploy>
</phases>
</lifecycle>
</lifecycles>
</configuration>
</component>
The role org.apache.maven.lifecycle.mapping.LifecycleMapping defines the lifecycle configuration. The role-hint is the packaging type that you use in your pom.

undefined element declaration 'xs:schema'

I am completely new to web service stuff.
I have to write rest web service client for a web service. The web service runs fine on SoapUI. WSDL file for the URL is provided to me. But when I add the wsdl file in my Eclipse project, it gives compilation error
src-resolve.4.2: Error resolving component 'xs:schema'. It was detected that 'xs:schema' is in namespace 'http://www.w3.org/2001/XMLSchema', but components from this namespace are not referenceable from schema document 'file:///E:/Ashish%20Workspace/HATStoLSAMS%20Webservice/HATS2LSAMSWS/WebContent/WEB-INF/wsdl/CorpsiteService.svc.wsdl'. If this is the incorrect namespace, perhaps the prefix of 'xs:schema' needs to be changed. If this is the correct namespace, then an appropriate 'import' tag should be added to 'file:///E:/Ashish%20Workspace/HATStoLSAMS%20Webservice/HATS2LSAMSWS/WebContent/WEB-INF/wsdl/CorpsiteService.svc.wsdl'.
I googled a lot to get rid of these error but nothing worked.
If I ignore the errors and try creating stubs using wsimport as well as wsdl2java commands
it gives error
[ERROR] undefined element declaration 'xs:schema'
line 1 of http://chec.local/STAR.WCF/CorpsiteService.svc?singlewsdl
I am using below command to generate stubs
wsimport -d e:\test -s E:\wssrc http://chec.local/STAR.WCF/CorpsiteService.svc?singlewsdl -wsdllocation "../../../../../WEB-INF/wsdl/CorpsiteService.svc.wsdl"
I am stuck at this point and have been struggling on to this the whole day.
Any help regarding this would be really helpful

The solution to this appears to be supply alternate bindings for xs:schema as described in https://metro.java.net/2.1/guide/Dealing_with_schemas_that_are_not_referenced.html
Specifically, for the http://www.w3.org/2001/XMLSchema which is often imported into the namespace xs, there is some additional work that needs to be done.
The command would be: wsimport -b http://www.w3.org/2001/XMLSchema.xsd -b customization.xjb something.wsdl
customization.xjb linked from the above is at https://www.java.net//blog/kohsuke/archive/20070228/xsd.xjb or copied from below
This customization exists to handle some naming conflicts that might arise from using the schema Schema (which is imported as the same name space in multiple schemas).
customization.xjb
<?xml version="1.0" encoding="UTF-8"?>
<bindings xmlns="http://java.sun.com/xml/ns/jaxb"
xmlns:xsd="http://www.w3.org/2001/XMLSchema"
xmlns:xjc="http://java.sun.com/xml/ns/jaxb/xjc"
version="2.0">
<globalBindings>
<xjc:simple />
</globalBindings>
<bindings scd="~xsd:complexType">
<class name="ComplexTypeType"/>
</bindings>
<bindings scd="~xsd:simpleType">
<class name="SimpleTypeType"/>
</bindings>
<bindings scd="~xsd:group">
<class name="GroupType"/>
</bindings>
<bindings scd="~xsd:attributeGroup">
<class name="AttributeGroupType"/>
</bindings>
<bindings scd="~xsd:element">
<class name="ElementType"/>
</bindings>
<bindings scd="~xsd:attribute">
<class name="attributeType"/>
</bindings>
</bindings>
I have tried this with these files and the associated -b parameters to wsimport and have gotten (apparently) past this error (and on to other ones). That said, I'm not 100% certain that my new errors are not in part caused by this (and thus this wouldn't be a complete answer). Without the actual wsdl causing the problem, one can only take a reasonable guess as to solving the problem (and on to the next one).

If you are using maven-jaxb2-plugin instead -b provide needed URL as additional schema in schemas:
<schema>
<url>https://example.com/WebService.asmx?WSDL</url>
</schema>
<schema>
<url>http://www.w3.org/2001/XMLSchema.xsd</url>
</schema>
You can even save it in resources so it is picked up automatically

I was facing same issue, resolved by just adding one line into maven plugin
<args>
<arg>-b</arg>
<arg>http://www.w3.org/2001/XMLSchema.xsd</arg>
</args>
My maven plugin is given below
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>jaxws-maven-plugin</artifactId>
<version>2.4.1</version>
<executions>
<execution>
<id>periodictableaccessws</id>
<goals>
<goal>wsimport</goal>
</goals>
<configuration>
<wsdlDirectory>${basedir}/src/main/resources/wsdl</wsdlDirectory>
<args>
<arg>-b</arg>
<arg>http://www.w3.org/2001/XMLSchema.xsd</arg>
</args>
<wsdlFiles>
<wsdlFile>doosdaas.wsdl</wsdlFile>
</wsdlFiles>
<packageName>com.dss.doosdaas</packageName>
<vmArgs>
<vmArg>-Djavax.xml.accessExternalDTD=all</vmArg>
<vmArg>-Djavax.xml.accessExternalSchema=all</vmArg>
</vmArgs>
<!-- <bindingDirectory>${basedir}/src/main/resources/jaxb</bindingDirectory>
<bindingFiles>
<bindingFile>jaxb_binding.xjb</bindingFile>
</bindingFiles>-->
</configuration>
</execution>
</executions>
</plugin>

I face this kind of error when I had to consume some of UE Taxations Customs web services. In previous projects I had used the solution proposed by user289086
But for recents projects I had used another solution also based in bindings but shorter, where I use the Wrapper-style rules described here Using JAXB Data Binding.
1- Create a binding file with the following content and add it to META-INF folder:
<jaxws:bindings xmlns:jaxws="http://java.sun.com/xml/ns/jaxws">
<jaxws:enableWrapperStyle>false</jaxws:enableWrapperStyle>
</jaxws:bindings>
2- Create Web service reference from wsdl using wsimport(in my case I use the Netbeans IDE WS Client Assistant that use wsimport in the background) for the following service for example:
UE CheckTinService
Note: First maybe the process of wsimport could be raise and error or not, but the difference of adding or not the previous binding is easy to check.
3- Add the binding reference to the corresponding jaxws-maven-plugin execution in the .pom file. For the example it stays like this:
<plugin>
<groupId>org.jvnet.jax-ws-commons</groupId>
<artifactId>jaxws-maven-plugin</artifactId>
<version>2.3</version>
<executions>
<execution>
<goals>
<goal>wsimport</goal>
</goals>
<configuration>
<wsdlFiles>
<wsdlFile>ec.europa.eu/taxation_customs/tin/checkTinService.wsdl</wsdlFile>
</wsdlFiles>
<packageName></packageName>
<vmArgs>
<vmArg>-Djavax.xml.accessExternalSchema=all</vmArg>
</vmArgs>
<wsdlLocation>https://ec.europa.eu/taxation_customs/tin/checkTinService.wsdl</wsdlLocation>
<staleFile>${project.build.directory}/jaxws/stale/checkTinService.stale</staleFile>
<bindingFiles>
<bindingFile>${basedir}/src/main/resources/META-INF/TaxationCustomsWsImportBindings.xml</bindingFile>
</bindingFiles>
</configuration>
<id>wsimport-generate-checkTinService</id>
<phase>generate-sources</phase>
</execution>
</executions>
...
You can see the exactly configuration for using the binding file created before:
<bindingFiles>
<bindingFile>${basedir}/src/main/resources/META-INF/TaxationCustomsWsImportBindings.xml</bindingFile>
</bindingFiles>
4- Finally turn to refresh de WS Reference and the changes will be applied to the process of wsimport.

Automatic verification of JavaDoc with Maven

During refactoring it happens frequently that JavaDoc gets out-of-date. It describes method arguments which are not present any more or some new ones are missing, to give examples.
It would be fine, if there is a Maven-plugin which automatically checks the existing JavaDoc and stops the build if there are some kind of "JavaDoc-violations".
I've seen the Maven-JavaDoc-Plugin and maven-doccheck, but both seem only to be able fix existing JavaDoc automatically in case of violations instead of bailing some error or warning.
Does anyone know how if there is some Maven-plugin like this and how to archive this?

As far as I know this is currently not possible with the maven-javadoc-plugin. There is the javadoc:fix mojo for the JavaDoc plugin, but this automatically fixes problems.
I recently created a JIRA entry for this problem: MJAVADOC-374 (which is acutally a duplicate of MJAVADOC-314).
Update:
You can use Checkstyle to verify correct JavaDoc. The configuration options are described here. Use the maven-checkstyle-plugin and the check-Mojo to integrate this into your maven build.
An example maven configuration could look like this:
<project>
...
<build>
<plugins>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-checkstyle-plugin</artifactId>
<version>2.15</version>
<configuration>
<logViolationsToConsole>true</logViolationsToConsole>
<checkstyleRules>
<module name="JavadocMethod">
<property name="scope" value="public"/>
<property name="allowUndeclaredRTE" value="true"/>
<property name="allowMissingParamTags" value="false"/>
</module>
</checkstyleRules>
</configuration>
</plugin>
</plugins>
</build>
...
</project>

In the Eclipe PMD plugin, can I reference the standard ruleset files?

I would like my eclipse PMD plugin configuration to access the same standard ruleset files as the maven-pmd-plugin.
You can configure the maven pmd plugin to use a custom set of rule sets like this:
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-pmd-plugin</artifactId>
<version>2.5</version>
<configuration>
<rulesets>
<!-- Two rule sets that come bundled with PMD -->
<ruleset>/rulesets/braces.xml</ruleset>
<ruleset>/rulesets/naming.xml</ruleset>
<!-- Custom local file system rule set -->
<ruleset>d:\rulesets\strings.xml</ruleset>
<!-- Custom remote rule set accessed via a URL -->
<ruleset>http://localhost/design.xml</ruleset>
</rulesets>
</configuration>
</plugin>
but in the eclipse plugin you can only switch on / turn off individual rules or specify a single ruleset file. Is there perhaps a way that ruleset file can include several others? Or do I have to aggregate that file automatically from the rulesets I want to use?

You can include other rulesets in a PMD ruleset file, e.g.
<ruleset ...>
...
<rule ref="rulesets/basic.xml"/>
...
<rule ref="rulesets/strings.xml">
<exclude name="AvoidDuplicateLiterals"/>
</rule>
...
</ruleset>
This is actually an excerpt from our own ruleset file, so it is proven to work :-)
As you can see, you can exclude/include individual rules from your ruleset, or even reconfigure them. One caveat: you must not mix rules for different languages in a single ruleset. I.e. in our case, we had to create separate rulesets for Java and JSP.
I learned the tricks myself from this page.