Develop Reference

When I am trying to run mvn dependency:tree , I am getting : java.lang.NoClassDefFoundError: org/sonatype/aether/version/VersionConstraint

I have no idea why this is happening. I tried deleting my m2 repository as well.
I tried with various versions of maven plugins(2.8) as well.
<dependency>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-dependency-plugin</artifactId>
<version>3.1.1</version>
</dependency>
Here is the complete stacktrace :
Error injecting: org.apache.maven.shared.dependency.graph.internal.Maven3DependencyGraphBuilder
java.lang.NoClassDefFoundError: org/sonatype/aether/version/VersionConstraint
at java.lang.Class.getDeclaredMethods0 (Native Method)
at java.lang.Class.privateGetDeclaredMethods (Class.java:2701)
at java.lang.Class.getDeclaredMethods (Class.java:1975)
at com.google.inject.spi.InjectionPoint.getDeclaredMethods (InjectionPoint.java:766)
at com.google.inject.spi.InjectionPoint.getInjectionPoints (InjectionPoint.java:683)
at com.google.inject.spi.InjectionPoint.forInstanceMethodsAndFields (InjectionPoint.java:378)
at com.google.inject.internal.ConstructorBindingImpl.getInternalDependencies
(ConstructorBindingImpl.java:181)
Caused by: java.lang.ClassNotFoundException: org.sonatype.aether.version.VersionConstraint
at org.codehaus.plexus.classworlds.strategy.SelfFirstStrategy.loadClass (SelfFirstStrategy.java:50)
at org.codehaus.plexus.classworlds.realm.ClassRealm.unsynchronizedLoadClass (ClassRealm.java:271)
at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass (ClassRealm.java:247)
at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass (ClassRealm.java:239)
at java.lang.Class.getDeclaredMethods0 (Native Method)
at java.lang.Class.privateGetDeclaredMethods (Class.java:2701)
at java.lang.Class.getDeclaredMethods (Class.java:1975)
at com.google.inject.spi.InjectionPoint.getDeclaredMethods (InjectionPoint.java:766)
at com.google.inject.spi.InjectionPoint.getInjectionPoints (InjectionPoint.java:683)
at com.google.inject.spi.InjectionPoint.forInstanceMethodsAndFields (InjectionPoint.java:378)

You can solve by using an older version of the plugin as indicated by the official page recalled by the error log:
mvn org.apache.maven.plugins:maven-dependency-plugin:2.8:tree

Update Maven version, at least to 3.0.x+ or 3.1.x+ see here
This error is caused by Maven 3.1-alpha-1 migration from Sonatype
Aether to Eclipse Aether (MNG-5354), which is an incompatible change
for some plugins.
Other report here claim to use Maven 3.3.0, so in any case, try with latest stable maven first (you can get it from here)
Side question: are you developing maven plugin? Usually you shouldn't declare dependencies on plugins in your pom.xml

Caused by: java.lang.NoClassDefFoundError: com_atlassian_clover/TestNameSniffer

Getting below error on invoking TestNG unit test cases with clover profile enabled. Did not change any clover version. Not getting any clue why its happening.
Here is my libs details - clover-4.0.3, testng - 6.0.1, maven 3
Caused by: java.lang.NoClassDefFoundError: com_atlassian_clover/TestNameSniffer
at com.mds404.catalog.infrastructure.entity.ModelBase.<clinit>(ModelBase.java:27)
at sun.reflect.GeneratedSerializationConstructorAccessor1.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Constructor.java:422)
at org.objenesis.instantiator.sun.SunReflectionFactoryInstantiator.newInstance(SunReflectionFactoryInstantiator.java:40)
at org.objenesis.ObjenesisBase.newInstance(ObjenesisBase.java:59)
at org.mockito.internal.creation.jmock.ClassImposterizer.createProxy(ClassImposterizer.java:111)
at org.mockito.internal.creation.jmock.ClassImposterizer.imposterise(ClassImposterizer.java:51)
at org.mockito.internal.util.MockUtil.createMock(MockUtil.java:52)
at org.mockito.internal.MockitoCore.mock(MockitoCore.java:41)
at org.mockito.Mockito.mock(Mockito.java:1014)
at org.mockito.Mockito.mock(Mockito.java:909)
at com.mds404.rest.v2.controller.BaseControllerTest.<init>(BaseControllerTest.java:107)
... 33 more
Caused by: java.lang.ClassNotFoundException: com_atlassian_clover.TestNameSniffer
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
at org.apache.maven.surefire.booter.IsolatedClassLoader.loadClass(IsolatedClassLoader.java:97)
... 46 more

The error
Caused by: java.lang.NoClassDefFoundError: com_atlassian_clover/TestNameSniffer
means that the Clover JAR (com.atlassian.clover:clover) is missing on the class path.
This is usually caused by two issues:
Missing com.atlassian.clover:clover dependency. Please note that the Clover Maven Plugin adds this dependency to the project automatically (during the build). However, in some cases, you have to add this dependency manually to other Maven plugins - usually to those which fork new JVM - for instance for in-container tests.
Build is running with Clover disabled but still failing on this error. This usually happens if you run the build with Clover enabled via 'clover:setup' and next install (or deploy) JARs created. When you run your build again, but this time with Clover disabled, the build can fetch these JARs from your ~/.m2 cache. As these JARs contain instrumented code and com.atlassian.clover:clover is missing, build will fail. To solve this problem, clean up your ~/.m2 cache and don't use "clover:setup" with "install" or "deploy".
Reference:
https://confluence.atlassian.com/cloverkb/noclassdeffounderror-com_atlassian_clover-coveragerecorder-317196439.html
Cheers
Marek

So finally what did help me here is adding another dependency of clover in dependencies tag. I already had this dependency as part of clover profile. But still I was getting above reported error.
After spending few hours when I added one more time same dependency next to all other libraries. As I was out of thoughts. And magically it did work.
Here is my updated pom.xml with both dependency copies -
...
<profile>
<id>clover</id>
<activation>
<activeByDefault>false</activeByDefault>
</activation>
<build>
<plugins>
<plugin>
<groupId>com.atlassian.maven.plugins</groupId>
<artifactId>maven-clover2-plugin</artifactId>
<version>4.0.3</version>
<configuration>
<methodContexts>
<toStr>(.* )?public .*(toString).*</toStr>
<hashCode>(.* )?public .*(hashCode).*</hashCode>
<equals>(.* )?public boolean equals\(Object.*\).*</equals>
<privateConstructors>(.* )?private +[a-zA-Z0-9]+ *\(\).*</privateConstructors>
</methodContexts>
<contextFilters>toStr,hashCode,equals,privateConstructors</contextFilters>
</configuration>
</plugin>
</plugins>
</build>
<dependencies>
<dependency>
<groupId>com.atlassian.clover</groupId>
<artifactId>clover</artifactId>
<version>4.0.3</version>
</dependency>
</dependencies>
</profile>
And then all other dependencies -
....
<dependencies>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>${org.springframework.version}</version>
</dependency>
<dependency>
<groupId>com.atlassian.clover</groupId>
<artifactId>clover</artifactId>
<version>4.0.3</version>
</dependency>
...

I stumbled across this error, that is, running my unit test I got
[ERROR] Tests run: 1, Failures: 0, Errors: 1, Skipped: 0, Time elapsed: 0.082 s <<< FAILURE! - in [...]
[ERROR] [...] Time elapsed: 0.017 s <<< ERROR!
java.lang.NoClassDefFoundError: com_atlassian_clover/TestNameSniffer
at [...]
Caused by: java.lang.ClassNotFoundException: com_atlassian_clover.TestNameSniffer
at [...]
First, let me say that this error really puzzled me, since I was sure that the same configuration of the project did not had this error before.
Here is what caused this error:
The project that exhibits the error references a dependency which I own or which I build and installed in my maven repository.
That dependency was mvn clean install-ed during a "Clover" run, that is, the version in .m2/repository had some clover code compiled into it.
Of course, this resulted in the other project pulling in some clover-instrumented code, without the required dependency.
The issue disappeared, once I have removed the dependency from my .m2/repository such that it was pulled from Maven central (which was clean and did not had the clover code).
Edit: Just saw that his was the second case in Mareks answer.

How to fix the maven check style error

Currently I just tried to download and build to make the Netty source code work. But when I tried to run the command mvn eclipse:eclipse in the source folder. I got an error said
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-checkstyle-plugin:2.10:check (check-style) on project netty-common: Failed during checkstyle execu
tion: There are 304 checkstyle errors. -> [Help 1]
org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal org.apache.maven.plugins:maven-checkstyle-plugin:2.10:check (check-style) on proj
ect netty-common: Failed during checkstyle execution
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:212)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145)
at org.apache.maven.lifecycle.internal.MojoExecutor.executeForkedExecutions(MojoExecutor.java:352)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:197)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:116)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:80)
at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build(SingleThreadedBuilder.java:51)
at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:128)
at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:307)
at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:193)
at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:106)
at org.apache.maven.cli.MavenCli.execute(MavenCli.java:863)
at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:288)
at org.apache.maven.cli.MavenCli.main(MavenCli.java:199)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:497)
at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:289)
at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:229)
at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:415)
at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:356)
Caused by: org.apache.maven.plugin.MojoExecutionException: Failed during checkstyle execution
at org.apache.maven.plugin.checkstyle.CheckstyleViolationCheckMojo.execute(CheckstyleViolationCheckMojo.java:374)
at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:134)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:207)
... 24 more
Caused by: org.apache.maven.plugin.checkstyle.CheckstyleExecutorException: There are 304 checkstyle errors.
at org.apache.maven.plugin.checkstyle.DefaultCheckstyleExecutor.executeCheckstyle(DefaultCheckstyleExecutor.java:218)
at org.apache.maven.plugin.checkstyle.CheckstyleViolationCheckMojo.execute(CheckstyleViolationCheckMojo.java:365)
It is error of the checkstyle plugin when validating the code netty-common project.
I am not familiar with this plugin . I want to know if I can just ignore it by removing the configuration from the pom.xml(in the ). like below.
<plugin>
<artifactId>maven-checkstyle-plugin</artifactId>
<version>2.10</version>
<executions>
<execution>
<id>check-style</id>
<goals>
<goal>check</goal>
</goals>
<phase>validate</phase>
<configuration>
<consoleOutput>true</consoleOutput>
<logViolationsToConsole>true</logViolationsToConsole>
<failsOnError>true</failsOnError>
<failOnViolation>true</failOnViolation>
<configLocation>io/netty/checkstyle.xml</configLocation>
<includeTestSourceDirectory>true</includeTestSourceDirectory>
</configuration>
</execution>
</executions>
<dependencies>
<dependency>
<groupId>${project.groupId}</groupId>
<artifactId>netty-build</artifactId>
<version>21</version>
</dependency>
</dependencies>
</plugin>
Any idea ? Thanks.

Skip the check style execution using
-Dcheckstyle.skip
Ex
mvn [YOUR_COMMAND] -Dcheckstyle.skip

CheckStyle is a module of maven that check the style of the code for things like tabs instead of spaces. Netty is using this to prevent basic formatting mistakes.
If you are planning to contribute to Netty, you should NOT remove the plugin as it probably means your patch will never applied.
If you are just using to play with, you are free to remove that plugin as its only purpose is to verify the installation, and not to change things from the installation.
If you choose to keep it, you should look in the output log to see what the mistakes are it detected, to quickly fix the mistakes, see this answer by Matthew Farwell.
Right click on the java file in Package Explorer or whatever, and select 'Apply Checkstyle Corrections'.
Click on the error in the problems view, and select 'Quick fix'. This corrects the problem.

Whereas I am neither familiar with Netty nor the maven eclipse plugin, I did face an issue with the maven-checkstyle-plugin while building the pwm project.
This was the error:
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-checkstyle-plugin:2.17:check (validate) on project pwm: Failed during checkstyle configuration ....
My Solution (which also solves many maven related errors btw):
Delete the maven's .m2 folder, then build the project again.
On linux systems, the .m2 folder is usually in your home folder /home/<username>/.m2

If you've just cloned the repository and the build failed, I believe you are using Windows and you have a problem with your Git configuration. Please set the 'core.autocrlf' option to 'true', re-clone the repository, and try again.
git config --global core.autocrlf true

I faced the same issue and I disabled checkstyle from pom, by adding the following in my pom file and it worked for me.
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-checkstyle-plugin</artifactId>
<executions>
<execution>
<id>checkstyle-validation</id>
<phase>none</phase>
</execution>
</executions>
</plugin>

On Linux OS I solved using dos2unix.
cd presto;
find . -type f -exec dos2unix {} \;

Just do "mvn spotless:apply", worked for me

In my case I just tried to execute same goal but with -X option (enabling debug level) and found what class check style plugin is complaining about. Corrected style and run maven again -> Build success.

Best approach to fix this issues by running the mvn install with -X option it will give you detail about the style issues in class. You can fix the class accordingly.

I solved this problem by removing the check-style configuration in my pom.xml and rebuilding maven. When I later re-inserted and build, it worked without error.

Jackson dependency version being overridden when doing maven build

I had a perfectly working project. I was able to do a successful build and deployment. Yesterday as a part of development I had to add the following maven dependencies for Jackson jars in my project after which the mvn clean install started to fail.
<dependency>
<groupId>org.codehaus.jackson</groupId>
<artifactId>jackson-mapper-asl</artifactId>
<version>1.5.3</version>
</dependency>
<dependency>
<groupId>org.codehaus.jackson</groupId>
<artifactId>jackson-core-asl</artifactId>
<version>1.5.3</version>
</dependency>
The error message that I get is
[ERROR] Failed to execute goal on project compass_app: Could not
resolve dependencies for project
com.XXXXX.services:compass_app:jar:1.0-SNAPSHOT: Failed to collect
depe dencies at org.codehaus.jackson:jackson-mapper-asl:jar:1.5.3 ->
org.codehaus.jackson:jackson-core-asl:jar:1.9.13: Failed to read
artifact descriptor for org.codehaus.jackson:jackson-core-asl:j
r:1.9.13: Could not transfer artifact
org.codehaus.jackson:jackson-core-asl:pom:1.9.13 from/to m-all
(http://XXXX/archives/all): Failed to transfer file:
http://XXXX/archives/all/org/codehaus/jackson/jackson-core-asl/1.9.13/jackson-core-asl-1.9.13.pom.
Return code is: 500 , ReasonPhrase:Unable to find managed repository
configuration for id:npanXXXX-1.5.0-maestXXXX-33. -> [Help 1]
My concern is why is the version 1.9.13 attempted for a download when I have not specified it anywhere in my project
I have only one declaration of jackson jars in my pom file.
I have tried doing a mvn -X clean install > install.txt .
Following pieces of trace may be helpful.
[DEBUG] Configuration: <?xml version="1.0" encoding="UTF-8"?>
<configuration>
<artifact default-value="${project.artifact}"/>
<attachedArtifacts default-value="${project.attachedArtifacts}"/>
<createChecksum default-value="false">${createChecksum}</createChecksum>
<localRepository>${localRepository}</localRepository>
<packaging default-value="${project.packaging}"/>
<pomFile default-value="${project.file}"/>
<updateReleaseInfo default-value="false">${updateReleaseInfo}</updateReleaseInfo>
</configuration>
The Exception is.
org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal on project compass_app: Could not resolve dependencies for project com.XXXX.services:compass_app:jar:1.0-SNAPSHOT: Failed to collect dependencies at org.codehaus.jackson:jackson-mapper-asl:jar:1.5.3 -> org.codehaus.jackson:jackson-core-asl:jar:1.9.13
at org.apache.maven.lifecycle.internal.LifecycleDependencyResolver.getDependencies(LifecycleDependencyResolver.java:220)
at org.apache.maven.lifecycle.internal.LifecycleDependencyResolver.resolveProjectDependencies(LifecycleDependencyResolver.java:127)
at org.apache.maven.lifecycle.internal.MojoExecutor.ensureDependenciesAreResolved(MojoExecutor.java:257)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:200)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:116)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:80)
at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build(SingleThreadedBuilder.java:51)
at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:120)
at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:347)
at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:154)
at org.apache.maven.cli.MavenCli.execute(MavenCli.java:584)
at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:213)
at org.apache.maven.cli.MavenCli.main(MavenCli.java:157)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:289)
at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:229)
at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:415)
at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:356)
Caused by: org.apache.maven.project.DependencyResolutionException: Could not resolve dependencies for project com.XXXX.services:compass_app:jar:1.0-SNAPSHOT: Failed to collect dependencies at org.codehaus.jackson:jackson-mapper-asl:jar:1.5.3 -> org.codehaus.jackson:jackson-core-asl:jar:1.9.13
at org.apache.maven.project.DefaultProjectDependenciesResolver.resolve(DefaultProjectDependenciesResolver.java:167)
at org.apache.maven.lifecycle.internal.LifecycleDependencyResolver.getDependencies(LifecycleDependencyResolver.java:195)
... 22 more
Any assistance will be greatly helpful. thanks in advance.
References :- The following links have already been referred.
1. jersey and jackson maven dependency issues?
2. http://maven.apache.org/ref/3.1.1/xref/org/apache/maven/artifact/resolver/DebugResolutionListener.html ( to understand the code and working of maven )
3. http://cwiki.apache.org/confluence/display/MAVEN/DependencyResolutionException

My concern is why is the version 1.9.13 attempted for a download when
I have not specified it anywhere in my project
Please use mvn dependency:tree (see: documentation) so that you will be able to track why this version is being loaded.
It is probably kind of transitive dependency.

Workspace defines a VM that does not contain a valid jre/lib/rt.jar: C:\Program Files\Java\jre7

I am new to maven and i have been creating simple web application with maven using hibernate, spring etc. i get following error occur when i run mvn eclipse:eclipse command.
[WARNING] Workspace defines a VM that does not contain a valid jre/lib/rt.jar: C:\Program Files\Java\jre7
[WARNING] could not read workspace project:c:\Users\Acer\workspace\.metadata\.plugins\org.eclipse.core.resources\.projects\myproject
org.codehaus.plexus.util.xml.pull.XmlPullParserException: processing instruction can not have PITarget with reserveld xml name (position: START_D
OCUMENT seen \r\n<?xml ... #2:7)
at org.codehaus.plexus.util.xml.pull.MXParser.parsePI(MXParser.java:2453)
at org.codehaus.plexus.util.xml.pull.MXParser.parseProlog(MXParser.java:1447)
at org.codehaus.plexus.util.xml.pull.MXParser.nextImpl(MXParser.java:1395)
at org.codehaus.plexus.util.xml.pull.MXParser.next(MXParser.java:1093)
at org.codehaus.plexus.util.xml.Xpp3DomBuilder.build(Xpp3DomBuilder.java:187)
at org.codehaus.plexus.util.xml.Xpp3DomBuilder.build(Xpp3DomBuilder.java:83)
at org.codehaus.plexus.util.xml.Xpp3DomBuilder.build(Xpp3DomBuilder.java:48)
at org.apache.maven.plugin.eclipse.reader.ReadWorkspaceLocations.readArtefact(ReadWorkspaceLocations.java:341)
at org.apache.maven.plugin.eclipse.reader.ReadWorkspaceLocations.readWorkspace(ReadWorkspaceLocations.java:536)
at org.apache.maven.plugin.eclipse.reader.ReadWorkspaceLocations.init(ReadWorkspaceLocations.java:94)
at org.apache.maven.plugin.eclipse.EclipsePlugin.getWorkspaceConfiguration(EclipsePlugin.java:2063)
at org.apache.maven.plugin.eclipse.EclipsePlugin.fillDefaultClasspathContainers(EclipsePlugin.java:1580)
at org.apache.maven.plugin.eclipse.EclipsePlugin.setup(EclipsePlugin.java:978)
at org.apache.maven.plugin.ide.AbstractIdeSupportMojo.execute(AbstractIdeSupportMojo.java:500)
at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:101)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:209)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:84)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:59)
at org.apache.maven.lifecycle.internal.LifecycleStarter.singleThreadedBuild(LifecycleStarter.java:183)
at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:161)
at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:320)
at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:156)
at org.apache.maven.cli.MavenCli.execute(MavenCli.java:537)
at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:196)
at org.apache.maven.cli.MavenCli.main(MavenCli.java:141)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:290)
at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:230)
at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:409)
at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:352)
[INFO] no substring wtp server match.
this is my pom.xml
could anybody tell me what i am doing wrong here. thanks in advance for any help

I was also getting the error:
[WARNING] Workspace defines a VM that does not contain a valid jre/lib/rt.jar: C:\Program Files\Java\jre6
but I don't get the
[WARNING] could not read workspace project:c:\Users\Acer\workspace.metadata.plugins\org.eclipse.core.resources.projects\myproject
(perhaps you were not setting your workspace path up correctly on the mvn command line by using the option -Declipse.workspace=...)
Anyway, the first warning was caused by me using a JDK in a non-standard place (JAVA_HOME=C:\tools\java\jdk1.6.0_31) and setting my Eclipse workspace up to use that as the default. The Maven Eclipse plugin does not seem to choose the default JDK correctly, The "mvn eclipse:eclipse" would not work until I removed the JDK in "C:\Program Files\Java\jre6" from the list of installed JDKs within Eclipse. I only have the correct one in the list now.

I looks like a java issue. Check your java_home directory. Is it pointing to C:\Program Files\Java\jre7 ? If so let maven also point to read same location by configure the toolchains.xml in your maven directory (e.g D:\maven-2.2.1\conf) to your java version
<toolchains>
<toolchain>
<type>jdk</type>
<provides>
<version>1.7</version> <!--This should be same as is configured via the toolchains plugin -->
<vendor>ibm</vendor> <!--This should be same as is configured via the toolchains plugin -->
</provides>
<configuration>
<jdkHome>C:\Program Files\Java\jdk1.7.0</jdkHome>
</configuration>
</toolchain>
</toolchains>

Add your own JRE, remove the default JRE installed in Eclipse. Yeah, it works.I could get no warning information when typing the command mvn eclipse:eclipse.

Try to store your maven projects in a directory that is not your eclipse workspace then import the projects to eclipse (without copying it!). Now the mvn eclipse:eclipse should work without warnings.

Seems to me maven fails to parse Eclipse's workspace settings properly. I was hitting the warning, and then I removed all JREs (I had two JREs and one JDK under Window-Preferences-Java-Installed JREs) and left only the JDK. No warnings since.

I am using Java 8, and I found that every time I did the eclipse:eclipse it was changing the JRE to JavaSE-1.7 instead of the JavaSE-1.8.
After more review of a bare bones pom.xml I saw the line in my properties section for maven.compiler.source and maven.compiler.target pointing to 1.7. Once I changed that to 1.8 everything works as expected.
I also have multiple version of Java setup. That didn't seem to be a problem. Updating this line seemed to do the trick, no more warnings when I do eclipse:eclipse now.
Hope it helps.