Spring boot REST Security

CustomAuthentication.java

import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import org.springframework.security.authentication.AuthenticationProvider;
import org.springframework.security.authentication.BadCredentialsException;
import org.springframework.security.authentication.UsernamePasswordAuthenticationToken;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.AuthenticationException;

/**
 * Created by asvignesh on 8/13/2019
 */
public class CustomAuthentication implements AuthenticationProvider {

  Map<String, String> usernamePasswordMap;

  public CustomAuthentication() {
    this.usernamePasswordMap = new HashMap<>();
    this.usernamePasswordMap.put("vignesh", "password");
    this.usernamePasswordMap.put("vignesh2", "password2");
  }

  @Override
  public Authentication authenticate(Authentication authentication) throws AuthenticationException {
    String user = authentication.getName();
    String password = authentication.getCredentials().toString();

    if (!usernamePasswordMap.containsKey(user)) {
      throw new BadCredentialsException("User doesn't exist");
    }
    String passwordStored = usernamePasswordMap.get(user);
    if (passwordStored.equals(password)) {
      return new UsernamePasswordAuthenticationToken(user, password, Collections.emptyList());
    } else {
      throw new BadCredentialsException("External system authentication failed");
    }
  }

  @Override
  public boolean supports(Class<?> aClass) {
    return true;
  }
}

SecurityConfig.java

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.security.authentication.AuthenticationProvider;
import org.springframework.security.config.annotation.authentication.builders.AuthenticationManagerBuilder;
import org.springframework.security.config.annotation.web.builders.HttpSecurity;
import org.springframework.security.config.annotation.web.configuration.WebSecurityConfigurerAdapter;

/**
 * Created by asvignesh on 8/13/2019
 */
@Configuration
public class SecurityConfig extends WebSecurityConfigurerAdapter {

  @Override
  protected void configure(HttpSecurity http) throws Exception {
    http.csrf().disable().authorizeRequests().anyRequest().authenticated().and().httpBasic();
  }

  @Autowired
  public void configureGlobal(AuthenticationManagerBuilder auth)
      throws Exception {
    AuthenticationProvider provider = new CustomAuthentication();
    auth.authenticationProvider(provider);
  }
}