AWSSecurityTokenServiceClientBuilder不再支持withCredentials方法，需要使用withCredentialsProvider方法代替。代码示例如下：

AWSSecurityTokenService stsClient = AWSSecurityTokenServiceClientBuilder.standard()
        .withRegion(region)
        .withCredentials(new DefaultAWSCredentialsProviderChain())
        .build();

应改为：

AWSSecurityTokenService stsClient = AWSSecurityTokenServiceClientBuilder.standard()
        .withRegion(region)
        .withCredentials(DefaultAWSCredentialsProviderChain.getInstance())
        .build();

注意：DefaultAWSCredentialsProviderChain.getInstance()代替了new DefaultAWSCredentialsProviderChain()，这是因为getInstance()方法是线程安全的，而new操作是非线程安全的。