HTTP Status 404 – Not Found for basic Spring Boot program - spring

Question

I receive the "HTTP Status 404 – Not Found" even though the Tomcat server seems to have initialized and running in the localhost:8080.
The pom.xml is
<?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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>org.springframework</groupId>
<artifactId>gs-consuming-rest</artifactId>
<version>0.1.0</version>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.1.6.RELEASE</version>
</parent>
<properties>
<java.version>1.8</java.version>
</properties>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
<exclusions>
<exclusion>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
<!--<scope>provided</scope>-->
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-web</artifactId>
<exclusions>
<exclusion>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
</exclusion>
</exclusions>
</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>
</plugin>
</plugins>
</build>
</project>
The Controller is
package com.example.demo;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
#RestController
public class HelloController {
#RequestMapping("/")
public String hello(){
return "Hello!";
}
}
The Main Application code is
package com.example.demo;
import java.util.Arrays;
import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.Bean;
#SpringBootApplication
public class HelloWorldApplication {
public static void main(String[] args) {
SpringApplication.run(HelloWorldApplication.class, args);
}
}
The console logs :
2019-08-09 19:53:07.161 INFO 13948 --- [ main] com.example.demo.HelloWorldApplication : Starting HelloWorldApplication on DESKTOP-BIMC3QL with PID 13948 (C:\Users\AdharshD\Documents\workspace-sts-3.9.9.RELEASE\HelloWorld\target\classes started by AdharshD in C:\Users\AdharshD\Documents\workspace-sts-3.9.9.RELEASE\HelloWorld)
2019-08-09 19:53:07.164 INFO 13948 --- [ main] com.example.demo.HelloWorldApplication : No active profile set, falling back to default profiles: default
2019-08-09 19:53:07.791 INFO 13948 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat initialized with port(s): 8080 (http)
2019-08-09 19:53:07.810 INFO 13948 --- [ main] o.apache.catalina.core.StandardService : Starting service [Tomcat]
2019-08-09 19:53:07.810 INFO 13948 --- [ main] org.apache.catalina.core.StandardEngine : Starting Servlet engine: [Apache Tomcat/9.0.21]
2019-08-09 19:53:07.891 INFO 13948 --- [ main] o.a.c.c.C.[Tomcat].[localhost].[/] : Initializing Spring embedded WebApplicationContext
2019-08-09 19:53:07.891 INFO 13948 --- [ main] o.s.web.context.ContextLoader : Root WebApplicationContext: initialization completed in 679 ms
2019-08-09 19:53:08.076 INFO 13948 --- [ main] o.s.b.w.embedded.tomcat.TomcatWebServer : Tomcat started on port(s): 8080 (http) with context path ''
2019-08-09 19:53:08.079 INFO 13948 --- [ main] com.example.demo.HelloWorldApplication : Started HelloWorldApplication in 1.211 seconds (JVM running for 1.855)

Answer 1

You are missing spring-boot-starter-web artifact. Artifact contains tells spring boot to scan the package (in which main method is present) and all his subpackage for configuration, components and controller. Since this artifact is missing, spring doesn’t register your controller and throws 404-Not found.