public Boolean isMfaDeleteEnabled() {
        return isMfaDeleteEnabled;
    }
Returns true if Multi-Factor Authentication (MFA) Delete is enabled for
this bucket versioning configuration, false if it isn't enabled, and null
if no information is available about the status of MFADelete.
<p>
When MFA Delete is enabled, object versions can only be permanently
deleted when the bucket owner passes in, as part of a delete version
request, an MFA token from the hardware token generator associated with
their Amazon Web Services account.
<p>
By default, MFA Delete is <b>not</b> enabled.
<p>
When enabling or disabling MFA Delete controls, you <b>must</b> also
supply an MFA token from the hardware token generator.

@return True if the Multi-Factor Authentication (MFA) Delete is enabled
        for this bucket versioning configuration, false if it isn't
        enabled, and null if no information is present on the status of
        MFA Delete.
aws-java-sdk-s3/src/main/java/com/amazonaws/services/s3/model/BucketVersioningConfiguration.java