@Configuration
@EnableResourceServer
public class ResourceServerConfiguration extends ResourceServerConfigurerAdapter {

    private static final String RESOURCE_ID = "my_rest_api";

    @Override
    public void configure(ResourceServerSecurityConfigurer resources) {
        resources.resourceId(RESOURCE_ID).stateless(false);
    }

    @Override
    public void configure(HttpSecurity http) throws Exception {
        http.
        anonymous().disable()
        .requestMatchers().antMatchers("/user/**")
        .and().authorizeRequests()
        .antMatchers("/user/**").access("hasRole('ADMIN')")
        .and().exceptionHandling().accessDeniedHandler(new OAuth2AccessDeniedHandler());
    }

}

@Configuration
@EnableAuthorizationServer
public class AuthorizationServerConfiguration extends AuthorizationServerConfigurerAdapter {

    @Autowired
    private TokenStore tokenStore;

    @Autowired
    private UserApprovalHandler userApprovalHandler;

    @Autowired
    @Qualifier("authenticationManagerBean")
    private AuthenticationManager authenticationManager;

    @Autowired
    private AuthorizationCodeServices authorizationCodeServices;

    @Override
    public void configure(ClientDetailsServiceConfigurer clients) throws Exception {

        clients.inMemory()
            .withClient("my-trusted-client")
            .authorizedGrantTypes("password", "authorization_code", "refresh_token", "implicit")
            .authorities("ROLE_CLIENT", "ROLE_TRUSTED_CLIENT")
            .scopes("read", "write", "trust")
            .secret("secret")
            .redirectUris("http://localhost:8080/clientapp/auth/callback")
            .autoApprove(true)
            .accessTokenValiditySeconds(120).//Access token is only valid for 2 minutes.
            refreshTokenValiditySeconds(600);//Refresh token is only valid for 10 minutes.
    }

    @Override
    public void configure(AuthorizationServerEndpointsConfigurer endpoints) throws Exception {
        endpoints.tokenStore(tokenStore).userApprovalHandler(userApprovalHandler)
        .authenticationManager(authenticationManager).authorizationCodeServices(authorizationCodeServices);
    }

    @Override
    public void configure(AuthorizationServerSecurityConfigurer oauthServer) throws Exception {
        oauthServer
            .tokenKeyAccess("permitAll()")
            .checkTokenAccess("isAuthenticated()");
    }

}

@Configuration
@EnableWebSecurity
public class OAuth2SecurityConfiguration extends WebSecurityConfigurerAdapter {

    @Autowired
    private ClientDetailsService clientDetailsService;

    @Autowired
    public void globalUserDetails(AuthenticationManagerBuilder auth) throws Exception {
        auth.inMemoryAuthentication()
        .withUser("bill").password("abc123").roles("ADMIN").and()
        .withUser("bob").password("abc123").roles("USER");
    }

    @Override
    protected void configure(HttpSecurity http) throws Exception {
        http
        .csrf().disable()
        .anonymous().disable()
        .authorizeRequests()
        .antMatchers("/oauth/authorize", "/oauth/token").permitAll();
    }

    @Override
    @Bean
    public AuthenticationManager authenticationManagerBean() throws Exception {
        return super.authenticationManagerBean();
    }

    @Bean
    protected AuthorizationCodeServices authorizationCodeServices() {
        return new InMemoryAuthorizationCodeServices();
    }

    @Bean
    public TokenStore tokenStore() {
        return new InMemoryTokenStore();
    }

    @Bean
    @Autowired
    public TokenStoreUserApprovalHandler userApprovalHandler(TokenStore tokenStore){
        TokenStoreUserApprovalHandler handler = new TokenStoreUserApprovalHandler();
        handler.setTokenStore(tokenStore);
        handler.setRequestFactory(new DefaultOAuth2RequestFactory(clientDetailsService));
        handler.setClientDetailsService(clientDetailsService);
        return handler;
    }

    @Bean
    @Autowired
    public ApprovalStore approvalStore(TokenStore tokenStore) throws Exception {
        TokenApprovalStore store = new TokenApprovalStore();
        store.setTokenStore(tokenStore);
        return store;
    }

}

<?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 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.pg.oauth2.example</groupId>
    <artifactId>oauth2-example</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>war</packaging>

    <name>oauth2-example</name>
    <description>OAuth2 Example</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.9.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.8</java.version>
    </properties>

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

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-tomcat</artifactId>
            <scope>provided</scope>
        </dependency>

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

        <dependency>
            <groupId>org.springframework.security.oauth</groupId>
            <artifactId>spring-security-oauth2</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

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


</project>