Spring application start error: sources must not be empty

14
votes

I'm following a Spring tutorial, and when I tried to start the spring application I got the following error:

2016-01-20 23:18:15.907 INFO 5271 --- [ main] o.s.boot.SpringApplication : Starting SpringApplication v1.3.1.RELEASE on ...

2016-01-20 23:18:15.911 INFO 5271 --- [ main] o.s.boot.SpringApplication : No active profile set, falling back to default profiles: default

2016-01-20 23:18:15.918 ERROR 5271 --- [ main] o.s.boot.SpringApplication : Application startup failed java.lang.IllegalArgumentException: Sources must not be empty at org.springframework.util.Assert.notEmpty(Assert.java:276) ~[spring-core-4.2.4.RELEASE.jar:4.2.4.RELEASE] at org.springframework.boot.SpringApplication.doRun(SpringApplication.java:352) [spring-boot-1.3.1.RELEASE.jar:1.3.1.RELEASE] at org.springframework.boot.SpringApplication.run(SpringApplication.java:305) [spring-boot-1.3.1.RELEASE.jar:1.3.1.RELEASE] at org.springframework.boot.SpringApplication.run(SpringApplication.java:1124) [spring-boot-1.3.1.RELEASE.jar:1.3.1.RELEASE] at org.springframework.boot.SpringApplication.main(SpringApplication.java:1140) [spring-boot-1.3.1.RELEASE.jar:1.3.1.RELEASE]

What is this "Sources must not be empty" error?

I am using an Eclipse - Maven project for this tutorial project and I have updated the project. I have also cleaned and rebuilt but I still got this error.

5
javaspringrest
Have a look at the doRun method and see what the assertion is checking – Marged
Please add the relevant section of code, so people can offer more useful suggestions. – betseyb
This can be caused by a dirty classpath with different versions of Spring libraries all over the place. Cleanup it and align it to the one and same Spring version with the correct versioned dependencies. – Pratap A.K
Please add the related code, especially your SpringBootApplication or EnableAutoConfiguration annotated class – Ali Dehghani

5 Answers

24
votes

It turns out that I did not set the main class correctly in Eclipse - Debug, and Run configuration.

I set org.springframework.boot.SpringApplication as the main class.

The Main class should be pointing to my main class.

9
votes

you must add at least one main config class as a source (see attached screenshots).

wrong: enter image description here

right: enter image description here

8
votes

Run the main class & not the project.

5
votes

Had the same issue recently, turned out I was running the wrong java class. I went to class where I have my @SpringBootApplication and right click -> run as java application. Hopefully that will help someone.

1
votes

add scanBasePackages="com.login" at main class thats all your code will work.

package com.login.example.LoginExample;

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

@SpringBootApplication(scanBasePackages="com.login")

public class LoginExampleApplication {

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