I am using Spring Tool Suite to work with ReST services in Java. But at the very first point I am not able to start my first simple application. Please help. I am getting below error. [Using Java8, STS suite, Ubuntu 16.04, $Java_Home: /usr/lib/jvm/java-8-oracle
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 :: Spring Boot ::        (v1.4.2.RELEASE)
2018-01-28 09:37:14.658  INFO 7971 --- [           main] i.j.springbootstarter.CourseApiApp       : Starting CourseApiApp on rudresh-Vostro-14-3468 with PID 7971 (/home/rudresh/Documents/workspace-sts-3.9.2.RELEASE/course-api/target/classes started by rudresh in /home/rudresh/Documents/workspace-sts-3.9.2.RELEASE/course-api)
2018-01-28 09:37:14.667  INFO 7971 --- [           main] i.j.springbootstarter.CourseApiApp       : No active profile set, falling back to default profiles: default
2018-01-28 09:37:14.827  INFO 7971 --- [           main] s.c.a.AnnotationConfigApplicationContext : Refreshing org.springframework.context.annotation.AnnotationConfigApplicationContext@6dde5c8c: startup date [Sun Jan 28 09:37:14 IST 2018]; root of context hierarchy
2018-01-28 09:37:16.551  WARN 7971 --- [           main] s.c.a.AnnotationConfigApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'org.springframework.boot.autoconfigure.web.HttpMessageConvertersAutoConfiguration$StringHttpMessageConverterConfiguration': Unsatisfied dependency expressed through constructor parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'spring.http.encoding-org.springframework.boot.autoconfigure.web.HttpEncodingProperties': Initialization of bean failed; nested exception is javax.validation.ValidationException: Unable to create a Configuration, because no Bean Validation provider could be found. Add a provider like Hibernate Validator (RI) to your classpath.
2018-01-28 09:37:16.552  INFO 7971 --- [           main] o.s.j.e.a.AnnotationMBeanExporter        : Unregistering JMX-exposed beans on shutdown
2018-01-28 09:37:16.568  INFO 7971 --- [           main] utoConfigurationReportLoggingInitializer : 
Error starting ApplicationContext. To display the auto-configuration report re-run your application with 'debug' enabled.
2018-01-28 09:37:16.578 ERROR 7971 --- [           main] o.s.b.d.LoggingFailureAnalysisReporter   : 
***************************
APPLICATION FAILED TO START
***************************
Description:
The Bean Validation API is on the classpath but no implementation could be found
Action:
Add an implementation, such as Hibernate Validator, to the classpath
Below is my POM.xml file. The whole example is taken from JavaBrains tutorial on YouTube for reference purpose. I suspect some issue either with Environment or the Hibernate validation which i have not installed in my system.
<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>io.javabrains.springbootquickstart</groupId>
  <artifactId>course-api</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <name>Java Brains Course Api</name>
<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.4.2.RELEASE</version>
  </parent>
  <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </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>
"This is main class to start SpringBoot application. Although it does not do anything but it should at least redirect to browser Error page."
package io.javabrains.springbootstarter;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
public class CourseApiApp {
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        SpringApplication.run(CourseApiApp.class, args);
    }
}
 
     
     
     
     
    