Maven profile snippet for smart appengine devserver restarts. It copies static files from src/main/webapp to target directory every time a change is detected. It also synchronizes compiled classes causing the Devserver to restart every time classes are changed.

maven profile

	<profile>
		<id>m2e</id>
		<activation>
			<property>
				<name>m2e.version</name>
			</property>
		</activation>
		<build>
			<plugins>
				<plugin>
					<groupId>org.apache.maven.plugins</groupId>
					<artifactId>maven-antrun-plugin</artifactId>
					<version>1.7</version>
					<executions>
						<execution>
							<phase>process-classes</phase>
							<goals>
								<goal>run</goal>
							</goals>
							<configuration>
								<target>
									<property name="target.webapp.dir"
										value="${project.build.directory}/${project.build.finalName}" />
									<property name="src.webapp.dir" value="${basedir}/src/main/webapp" />

									<sync verbose="true" todir="${target.webapp.dir}"
										includeEmptyDirs="true">
										<fileset dir="${src.webapp.dir}" />
										<preserveintarget>
											<include name="WEB-INF/lib/**" />
											<include name="WEB-INF/classes/**" />
											<include name="WEB-INF/appengine-generated/**" />
										</preserveintarget>
									</sync>

                  <sync verbose="true" todir="${target.webapp.dir}/WEB-INF/classes">
										<fileset dir="${basedir}/target/classes" />
									</sync>

								</target>
							</configuration>
						</execution>
					</executions>
				</plugin>
			</plugins>
			<pluginManagement>
				<plugins>
					<!-- This plugin's configuration is used to store Eclipse m2e settings 
						only. It has no influence on the Maven build itself. -->
					<plugin>
						<groupId>org.eclipse.m2e</groupId>
						<artifactId>lifecycle-mapping</artifactId>
						<version>1.0.0</version>
						<configuration>
							<lifecycleMappingMetadata>
								<pluginExecutions>
									<pluginExecution>
										<pluginExecutionFilter>
											<groupId>org.apache.maven.plugins</groupId>
											<artifactId>maven-antrun-plugin</artifactId>
											<versionRange>[1.6,)</versionRange>
											<goals>
												<goal>run</goal>
											</goals>
										</pluginExecutionFilter>
										<action>
											<execute>
												<runOnIncremental>true</runOnIncremental>
											</execute>
										</action>
									</pluginExecution>
								</pluginExecutions>
							</lifecycleMappingMetadata>
						</configuration>
					</plugin>
				</plugins>
			</pluginManagement>
		</build>
	</profile>