public Builder mergePrincipal(com.google.cloud.vmwareengine.v1.Principal value) {
      if (principalBuilder_ == null) {
        if (((bitField0_ & 0x00000002) != 0)
            && principal_ != null
            && principal_ != com.google.cloud.vmwareengine.v1.Principal.getDefaultInstance()) {
          getPrincipalBuilder().mergeFrom(value);
        } else {
          principal_ = value;
        }
      } else {
        principalBuilder_.mergeFrom(value);
      }
      if (principal_ != null) {
        bitField0_ |= 0x00000002;
        onChanged();
      }
      return this;
    }
<pre>
Required. The consumer provided user/service account which needs to be
granted permission to bind with the intranet VPC corresponding to the
consumer project.
</pre>

<code>
.google.cloud.vmwareengine.v1.Principal principal = 2 [(.google.api.field_behavior) = REQUIRED];
</code>
java-vmwareengine/proto-google-cloud-vmwareengine-v1/src/main/java/com/google/cloud/vmwareengine/v1/RevokeDnsBindPermissionRequest.java