Error creating bean with name 'springSecurityFilterChain'

Question

I copied your spring security configuration and was able to reproduce the error.

Following line in the stacktrace gives the root cause of the exception:

at org.springframework.security.provisioning.InMemoryUserDetailsManager.createUser(InMemoryUserDetailsManager.java:59)

In InMemoryUserDetailsManager class, createUser() method, Spring checks if the user exists before creating an user. In your case you are adding two user with same username, hence there is an IllegalArgumentException.

I added two users with different usernames and it started working fine.

I had the same problem. I fixed it deleting http.antMatchers("").The problem was "" - SpringSecurityFilterChain throws an error, because pattern could not be empty or null.

With java 11 please add this to pom file

<dependency>
        <groupId>com.sun.xml.bind</groupId>
        <artifactId>jaxb-core</artifactId>
        <version>2.3.0.1</version>
    </dependency>
    <dependency>
        <groupId>javax.xml.bind</groupId>
        <artifactId>jaxb-api</artifactId>
        <version>2.3.1</version>
    </dependency>
    <dependency>
        <groupId>com.sun.xml.bind</groupId>
        <artifactId>jaxb-impl</artifactId>
        <version>2.3.1</version>
    </dependency>

Simply, You can't create 2 users with same user name. But passwords can be same. Just rename the username

Fixed it by changing .antMatchers("/api/", "") to .antMatchers("/api/")