public static void main()

in solution/solution-ecs-sts-token/code-example/java/common/src/main/java/org/example/oss_sdk/CredentialsDefaultSample.java [20:67]
32 lines of code
1 McCabe index (conditional complexity)

    public static void main(String[] args) {
        // 初始化凭据客户端
        Config credentialConfig = new Config();
        credentialConfig.setType("ecs_ram_role");
        // 选填，该ECS角色的角色名称，不填会自动获取，建议加上以减少请求次数
        credentialConfig.setRoleName("<your-ecs-instance-role-name>");
        // 在加固模式下获取STS Token，强烈建议开启
        credentialConfig.setEnableIMDSv2(true);
        Client credentialClient = new Client(credentialConfig);

        // Bucket所在地域对应的Endpoint。以华东1（杭州）为例。
        String endpoint = "https://oss-cn-hangzhou.aliyuncs.com";
        // Endpoint对应的Region信息，例如cn-hangzhou。
        String region = "cn-hangzhou";
        // 建议使用更安全的V4签名算法，则初始化时需要加入endpoint对应的region信息，同时声明SignVersion.V4
        // OSS Java SDK 3.17.4及以上版本支持V4签名。
        ClientBuilderConfiguration configuration = new ClientBuilderConfiguration();
        configuration.setSignatureVersion(SignVersion.V4);

        // 用凭据客户端初始化OSS客户端
        OSS ossClient = OSSClientBuilder.create()
            .endpoint(endpoint)
            .credentialsProvider(new CredentialsProvider() {
                @Override
                public void setCredentials(Credentials credentials) {
                }

                @Override
                public Credentials getCredentials() {
                    // 保证线程安全，从 CredentialModel 中获取 ak/sk/security token
                    CredentialModel credentialModel = credentialClient.getCredential();
                    String ak = credentialModel.getAccessKeyId();
                    String sk = credentialModel.getAccessKeySecret();
                    String token = credentialModel.getSecurityToken();
                    return new DefaultCredentials(ak, sk, token);
                }
            })
            .clientConfiguration(configuration)
            .region(region)
            .build();

        // 调用OSS API
        List<Bucket> buckets = ossClient.listBuckets();
        System.out.println(JSON.toJSONString(buckets));

        // 关闭OSSClient。
        ossClient.shutdown();
    }