[FIXED] While I am running my Spring Boot application, I am getting the below error. I am using spring boot version 2.4.5

Issue

ERROR

2021-04-21 11:12:26.858 INFO 8064 --- [ main] o.s.boot.SpringApplication : Starting SpringApplication v2.4.5 using Java 15.0.2 on DESKTOP-MNKN1R7 with PID 8064 (C:\Users.m2\repository\org\springframework\boot\spring-boot\2.4.5\spring-boot-2.4.5.jar started by in C:\Users\Documents\demo)

2021-04-21 11:12:26.863 INFO 8064 --- [ main] o.s.boot.SpringApplication : No active profile set, falling back to default profiles: default

2021-04-21 11:12:26.928 ERROR 8064 --- [ main] o.s.boot.SpringApplication : Application run failed

java.lang.IllegalArgumentException: Sources must not be empty

at org.springframework.util.Assert.notEmpty(Assert.java:470) ~[spring-core-5.3.6.jar:5.3.6] at org.springframework.boot.SpringApplication.prepareContext(SpringApplication.java:425) ~[spring-boot-2.4.5.jar:2.4.5] at org.springframework.boot.SpringApplication.run(SpringApplication.java:338) ~[spring-boot-2.4.5.jar:2.4.5] at org.springframework.boot.SpringApplication.run(SpringApplication.java:1340) ~[spring-boot-2.4.5.jar:2.4.5] at org.springframework.boot.SpringApplication.main(SpringApplication.java:1356) ~[spring-boot-2.4.5.jar:2.4.5]

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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.4.5</version>
    <relativePath/> <!-- lookup parent from repository -->
</parent>
<groupId>com.example</groupId>
<artifactId>demo</artifactId>
<version>0.0.1-SNAPSHOT</version>
<name>demo</name>
<description>Demo project for spring annotations</description>
<properties>
    <java.version>1.8</java.version>
</properties>
<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter</artifactId>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
    
    <!-- https://mvnrepository.com/artifact/org.springframework/spring-core -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-core</artifactId>
        <version>5.3.6</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.springframework/spring-context -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-context</artifactId>
        <version>5.3.6</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.springframework/spring-web -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-web</artifactId>
        <version>5.3.6</version>
    </dependency>
    <!-- https://mvnrepository.com/artifact/org.springframework/spring-beans -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-beans</artifactId>
        <version>5.3.6</version>
    </dependency>
    
    
</dependencies>

<build>
    <plugins>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
        </plugin>
    </plugins>
</build>

</project>

DemoApplication.java

package com.example.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class DemoApplication {

public static void main(String[] args) {
    SpringApplication.run(DemoApplication.class, args);
}

}

Solution

<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>

Try changing your dependencies to something like this. I think you may be missing some dependencies。Some of the following dependencies like spring-web do not need to be configured because spring-boot-starter-web is already included

Answered By - caixiaomao
Answer Checked By - Dawn Plyler (JavaFixing Volunteer)