Liberty profile not able to detect Spring Boot componentscan annotation and not loading application context - spring-boot

Question

I am deploying Spring Boot web application in Liberty 16.0.0.3.Have provided all dependency scope as provided and configured global shared library.But when I start the application Liberty not been able to load application context.
My configuration as below.
My pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.myapp.testapp</groupId>
<artifactId>testsharedlib</artifactId>
<version>1.0.0-SNAPSHOT</version>
<packaging>war</packaging>
<name>testsharedlib</name>
<description>Demo project for Spring Boot</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.4.3.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
<runtime.scope>provided</runtime.scope>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<scope>${runtime.scope}</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-ws</artifactId>
<scope>${runtime.scope}</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<!-- <version>2.3</version> -->
<executions>
<execution>
<goals>
<goal>repackage</goal>
</goals>
<configuration>
<skip>true</skip>
<!-- <failOnMissingWebXml>false</failOnMissingWebXml> -->
</configuration>
</execution>
</executions>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-war-plugin</artifactId>
<configuration>
<failOnMissingWebXml>false</failOnMissingWebXml>
<packagingExcludes>WEB-INF/lib/*.jar</packagingExcludes>
<archive>
<manifest>
<mainClass>com.myapp.testapp.Appconfig</mainClass>
<addClasspath>true</addClasspath>
<classpathPrefix>lib/</classpathPrefix>
</manifest>
<manifestEntries>
<DisableIBMJAXWSEngine>true</DisableIBMJAXWSEngine>
<Class-Path>conf</Class-Path>
</manifestEntries>
</archive>
</configuration>
</plugin>
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-compiler-plugin</artifactId>
<configuration>
<source>1.8</source>
<target>1.8</target>
</configuration>
</plugin>
<plugin>
<artifactId>maven-resources-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
Liberty server.xml
<server description="Default Server">
<featureManager>
<feature>webProfile-7.0</feature>
<feature>localConnector-1.0</feature>
</featureManager>
<library id="global">
<fileset dir="${server.config.dir}/lib/jars" includes="*.jar"/>
</library>
<application context-root="HelloWorld" location="text-1.0.0-SNAPSHOT.war">
<classloader commonLibraryRef="global" delegation="parentFirst"/>
</application>
<!-- Define the host name for use by the collective.
If the host name needs to be changed, the server should be
removed from the collective and re-joined. -->
<variable name="defaultHostName" value="localhost"/>
<keyStore id="defaultKeyStore" password="adminpwd"/>
<!-- Define an Administrator and non-Administrator -->
<basicRegistry id="basic">
<user name="admin" password="adminpwd"/>
<user name="nonadmin" password="nonadminpwd"/>
</basicRegistry>
<!-- Assign 'admin' to Administrator -->
<administrator-role>
<user>admin</user>
</administrator-role>
<webContainer deferServletLoad="false"/>
<applicationManager autoExpand="true"/>
<httpEndpoint host="*" httpPort="9080" httpsPort="9443" id="defaultHttpEndpoint"/>
<logging consoleLogLevel="INFO" traceSpecification="*=info:com.ibm.ws.classloading.*=ALL"/>
</server>

Answer 1

The reason why this works with dependencies in WEB-INF/lib and not in a global shared lib is because the servlet that initializes your Spring application (org.springframework.web.servlet.DispatcherServlet) is coming from one of the jar dependencies. Liberty will only scan the web context root (i.e. WEB-INF/*) for servlet classes. It will not scan shared libraries for servlet classes.
As you found out in your other answer, the only way to link up a servlet coming from a jar in a shared lib is to explicitly declare it in web.xml (since Liberty will not auto-scan for it like it does for classes or jars in WEB-INF/*.
To confirm this, I wrote a simple servlet:
#WebServlet("/LibServlet")
public class LibServlet extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException
{
response.getWriter().append("Served at: ").append(request.getContextPath());
}
}
Then I packaged this servlet into servletLib.jar. When I provided this lib to my application using a shared library, I was not able to access the servlet at http://localhost:9080/testapp/LibServlet. However, when I moved servletLib.jar into a WEB-INF/lib then the servlet was accessible.

Answer 2

I am able to make it work by providing WEB-INF/web.xml in Liberty with global shared Library. Find below sample configuration.
pom.xml
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.myapp.testapp</groupId>
<artifactId>testsharedlib</artifactId>
<version>1.0.0-SNAPSHOT</version>
<packaging>war</packaging>
<name>testsharedlib</name>
<description>Demo project for Spring Boot</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.4.3.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
<runtime.scope>provided</runtime.scope>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
<scope>${runtime.scope}</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-ws</artifactId>
<scope>${runtime.scope}</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
<executions>
<execution>
<goals>
<goal>repackage</goal>
</goals>
<configuration>
<skip>true</skip>
</configuration>
</execution>
</executions>
</plugin>
<plugin>
<artifactId>maven-resources-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>
server.xml
<featureManager>
<feature>webProfile-7.0</feature>
<feature>localConnector-1.0</feature>
</featureManager>
<library id="global">
<fileset dir="${server.config.dir}/lib/jars" includes="*.jar"/>
</library>
<application context-root="HelloWorld" location="text-1.0.0-SNAPSHOT.war">
<classloader commonLibraryRef="global" delegation="parentLast"/>
</application>
<!-- Define the host name for use by the collective.
If the host name needs to be changed, the server should be
removed from the collective and re-joined. -->
<variable name="defaultHostName" value="localhost"/>
<keyStore id="defaultKeyStore" password="adminpwd"/>
<!-- Define an Administrator and non-Administrator -->
<basicRegistry id="basic">
<user name="admin" password="adminpwd"/>
<user name="nonadmin" password="nonadminpwd"/>
</basicRegistry>
<!-- Assign 'admin' to Administrator -->
<administrator-role>
<user>admin</user>
</administrator-role>
<webContainer deferServletLoad="false"/>
<applicationManager autoExpand="true"/>
<httpEndpoint host="*" httpPort="9080" httpsPort="9443" id="defaultHttpEndpoint"/>
<logging consoleLogLevel="INFO" traceSpecification="*=info:com.ibm.ws.classloading.*=ALL"/>
</server>
web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1">
<display-name>pctext</display-name>
<servlet>
<servlet-name>dispatcher</servlet-name>
<servlet-class>
org.springframework.web.servlet.DispatcherServlet
</servlet-class>
<init-param>
<param-name>contextClass</param-name>
<param-value>org.springframework.web.context.support.AnnotationConfigWebApplicationContext</param-value>
</init-param>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>com.myapp.testpkg.ApplicationConfig</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
<servlet-name>dispatcher</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
</web-app>
ApplicationConfig.java
#SpringBootApplication(scanBasePackages={"com.myapp.testpkg"})
public class ApplicationConfig {
public static void main(String[] args) {
SpringApplication.run(ApplicationConfig.class, args);
}
}