In a J2EE project environment, the master project is "sample-project", the web project is "sample-project-web" If set the property maven.eclipse.output.dir=web-content/WEB-INF/classes in the sample-project-web project The result .classpath created by the Eclipse plugin has the following entry: <classpathentry kind="output" path="C:/maven_projects/sample-project/web-content/WEB-INF/classes"> </classpathentry> This is wrong. The path value should be a relative path. Solution: change the following line in the classpath.jelly from: <j:set var="outputDir" value="${maven.eclipse.output.dir}"/> <j:if test="${empty outputDir}"> <j:set var="outputDir" value="${maven.build.dest}"/> </j:if> <maven:makeRelativePath var="outputDir" basedir="${basedir}" path="${outputDir}" separator="/"/> <classpathentry kind="output" path="${outputDir}"/> <ant:echo>Setting default output directory to ${outputDir}</ant:echo> to <j:set var="outputDir" value="${maven.eclipse.output.dir}"/> <j:if test="${empty outputDir}"> <j:set var="outputDir" value="${maven.build.dest}"/> <maven:makeRelativePath var="outputDir" basedir="${basedir}" path="${outputDir}" separator="/"/> </j:if> <classpathentry kind="output" path="${outputDir}"/> <ant:echo>Setting default output directory to ${outputDir}</ant:echo> With a requirement that the maven.eclipse.output.dir should always be set as a relative path. This requirement should be put in the plugin properties doc.