How to set proxy on spring oauth2 OAuth2AccessToken request or How to override OAuth2AccessTokenSupport restTemplate variable?

Another way to do this is by setting a custom AccessTokenProvider to your OAuth2RestTemplate. In the code sample below the SSL validation is bypassed :

@Configuration
public class ConfigLocal {

    @Value("${https.proxyHost}")
    private String proxyHost;

    @Value("${https.proxyPort}")
    private Integer proxyPort;

    @Value("${https.proxyUser}")
    private String proxyUser;

    @Value("${https.proxyPassword}")
    private String proxyPassword;

    @Bean
    public OAuth2RestTemplate oauth2RestTemplate(ClientCredentialsResourceDetails clientCredentialsResourceDetails)
            throws KeyManagementException, KeyStoreException, NoSuchAlgorithmException {
        OAuth2RestTemplate restTemplate = new OAuth2RestTemplate(clientCredentialsResourceDetails);

        // Instanciate a new http client with proxy configuration, and bypass SSL Certificate verification
        CredentialsProvider credentialsProvider = new BasicCredentialsProvider();
        credentialsProvider.setCredentials(AuthScope.ANY, new UsernamePasswordCredentials(proxyUser, proxyPassword));

        HttpClientBuilder httpClientBuilder =
                HttpClients.custom()
                        .setProxy(new HttpHost(proxyHost, proxyPort))
                        .setDefaultCredentialsProvider(credentialsProvider)
                        .setSSLHostnameVerifier(new NoopHostnameVerifier())
                            .setSSLContext(new SSLContextBuilder().loadTrustMaterial(null, (x509Certificates, s) -> true)
                                    .build());

        // requestFactory
        HttpComponentsClientHttpRequestFactory requestFactory = new HttpComponentsClientHttpRequestFactory(httpClientBuilder.build());
        ClientCredentialsAccessTokenProvider clientCredentialsAccessTokenProvider = new ClientCredentialsAccessTokenProvider();
        clientCredentialsAccessTokenProvider.setRequestFactory(requestFactory);

        // accessTokenProvider
        AccessTokenProvider accessTokenProvider = new AccessTokenProviderChain(Arrays.<AccessTokenProvider> asList(
                new AuthorizationCodeAccessTokenProvider(), new ImplicitAccessTokenProvider(),
                new ResourceOwnerPasswordAccessTokenProvider(), clientCredentialsAccessTokenProvider));

        restTemplate.setAccessTokenProvider(accessTokenProvider);

        return restTemplate;
    }
}