What is username and password when starting Spring Boot with Tomcat?

Question

I think that you have Spring Security on your class path and then spring security is automatically configured with a default user and generated password

Please look into your pom.xml file for:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-security</artifactId>
</dependency>

If you have that in your pom than you should have a log console message like this:

Using default security password: ce6c3d39-8f20-4a41-8e01-803166bb99b6

And in the browser prompt you will import the user user and the password printed in the console.

Or if you want to configure spring security you can take a look at Spring Boot secured example

It is explained in the Spring Boot Reference documentation in the Security section, it indicates:

The default AuthenticationManager has a single user (‘user’ username and random password, printed at `INFO` level when the application starts up)

Using default security password: 78fa095d-3f4c-48b1-ad50-e24c31d5cf35

If spring-security jars are added in classpath and also if it is spring-boot application all http endpoints will be secured by default security configuration class SecurityAutoConfiguration

This causes a browser pop-up to ask for credentials.

The password changes for each application restarts and can be found in console.

Using default security password: 78fa095d-3f4c-48b1-ad50-e24c31d5cf35

To add your own layer of application security in front of the defaults,

@EnableWebSecurity
public class SecurityConfig {

    @Autowired
    public void configureGlobal(AuthenticationManagerBuilder auth) throws Exception {
        auth
            .inMemoryAuthentication()
                .withUser("user").password("password").roles("USER");
    }
}

or if you just want to change password you could override default with,

application.xml

security.user.password=new_password

or

application.properties

spring.security.user.name=<>
spring.security.user.password=<>

When overriding

spring.security.user.name=
spring.security.user.password=

in application.properties, you don't need " around "username", just use username. Another point, instead of storing raw password, encrypt it with bcrypt/scrypt and store it like

spring.security.user.password={bcrypt}encryptedPassword

If you can't find the password based on other answers that point to a default one, the log message wording in recent versions changed to

Using generated security password: <some UUID>

You can also ask the user for the credentials and set them dynamically once the server starts (very effective when you need to publish the solution on a customer environment):

@EnableWebSecurity
public class SecurityConfig {

    private static final Logger log = LogManager.getLogger();

    @Autowired
    public void configureGlobal(AuthenticationManagerBuilder auth) throws Exception {
        log.info("Setting in-memory security using the user input...");

        Scanner scanner = new Scanner(System.in);
        String inputUser = null;
        String inputPassword = null;
        System.out.println("\nPlease set the admin credentials for this web application");
        while (true) {
            System.out.print("user: ");
            inputUser = scanner.nextLine();
            System.out.print("password: ");
            inputPassword = scanner.nextLine();
            System.out.print("confirm password: ");
            String inputPasswordConfirm = scanner.nextLine();

            if (inputUser.isEmpty()) {
                System.out.println("Error: user must be set - please try again");
            } else if (inputPassword.isEmpty()) {
                System.out.println("Error: password must be set - please try again");
            } else if (!inputPassword.equals(inputPasswordConfirm)) {
                System.out.println("Error: password and password confirm do not match - please try again");
            } else {
                log.info("Setting the in-memory security using the provided credentials...");
                break;
            }
            System.out.println("");
        }
        scanner.close();

        if (inputUser != null && inputPassword != null) {
             auth.inMemoryAuthentication()
                .withUser(inputUser)
                .password(inputPassword)
                .roles("USER");
        }
    }
}

(May 2018) An update - this will work on spring boot 2.x:

@Configuration
public class SecurityConfig extends WebSecurityConfigurerAdapter {

    private static final Logger log = LogManager.getLogger();

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        // Note: 
        // Use this to enable the tomcat basic authentication (tomcat popup rather than spring login page)
        // Note that the CSRf token is disabled for all requests
        log.info("Disabling CSRF, enabling basic authentication...");
        http
        .authorizeRequests()
            .antMatchers("/**").authenticated() // These urls are allowed by any authenticated user
        .and()
            .httpBasic();
        http.csrf().disable();
    }

    @Bean
    public UserDetailsService userDetailsService() {
        log.info("Setting in-memory security using the user input...");

        String username = null;
        String password = null;

        System.out.println("\nPlease set the admin credentials for this web application (will be required when browsing to the web application)");
        Console console = System.console();

        // Read the credentials from the user console: 
        // Note: 
        // Console supports password masking, but is not supported in IDEs such as eclipse; 
        // thus if in IDE (where console == null) use scanner instead:
        if (console == null) {
            // Use scanner:
            Scanner scanner = new Scanner(System.in);
            while (true) {
                System.out.print("Username: ");
                username = scanner.nextLine();
                System.out.print("Password: ");
                password = scanner.nextLine();
                System.out.print("Confirm Password: ");
                String inputPasswordConfirm = scanner.nextLine();

                if (username.isEmpty()) {
                    System.out.println("Error: user must be set - please try again");
                } else if (password.isEmpty()) {
                    System.out.println("Error: password must be set - please try again");
                } else if (!password.equals(inputPasswordConfirm)) {
                    System.out.println("Error: password and password confirm do not match - please try again");
                } else {
                    log.info("Setting the in-memory security using the provided credentials...");
                    break;
                }
                System.out.println("");
            }
            scanner.close();
        } else {
            // Use Console
            while (true) {
                username = console.readLine("Username: ");
                char[] passwordChars = console.readPassword("Password: ");
                password = String.valueOf(passwordChars);
                char[] passwordConfirmChars = console.readPassword("Confirm Password: ");
                String passwordConfirm = String.valueOf(passwordConfirmChars);

                if (username.isEmpty()) {
                    System.out.println("Error: Username must be set - please try again");
                } else if (password.isEmpty()) {
                    System.out.println("Error: Password must be set - please try again");
                } else if (!password.equals(passwordConfirm)) {
                    System.out.println("Error: Password and Password Confirm do not match - please try again");
                } else {
                    log.info("Setting the in-memory security using the provided credentials...");
                    break;
                }
                System.out.println("");
            }
        }

        // Set the inMemoryAuthentication object with the given credentials:
        InMemoryUserDetailsManager manager = new InMemoryUserDetailsManager();
        if (username != null && password != null) {
            String encodedPassword = passwordEncoder().encode(password);
            manager.createUser(User.withUsername(username).password(encodedPassword).roles("USER").build());
        }
        return manager;
    }

    @Bean
    public PasswordEncoder passwordEncoder() {
        return new BCryptPasswordEncoder();
    }
}

Addition to accepted answer -

If password not seen in logs, enable "org.springframework.boot.autoconfigure.security" logs.

If you fine-tune your logging configuration, ensure that the org.springframework.boot.autoconfigure.security category is set to log INFO messages, otherwise the default password will not be printed.

https://docs.spring.io/spring-boot/docs/1.4.0.RELEASE/reference/htmlsingle/#boot-features-security

For a start simply add the following to your application.properties file

spring.security.user.name=user
spring.security.user.password=pass

NB: with no double quote

Run your application and enter the credentials (user, pass)