| Name | Description | Type | Package | Framework |
| Descriptors | Contains a collection of classes which describe protocol message types. | Class | akka.protobuf | Akka |
| Descriptors .Descriptor | Describes a message type. | Class | akka.protobuf.Descriptors | Akka |
| Descriptors .DescriptorValidationException | Thrown when building descriptors fails because the source DescriptorProtosSee Also:Serialized Form | Class | akka.protobuf.Descriptors | Akka |
| Descriptors .EnumDescriptor | Describes an enum type. | Class | akka.protobuf.Descriptors | Akka |
| Descriptors .EnumValueDescriptor | Describes one value within an enum type. | Class | akka.protobuf.Descriptors | Akka |
| Descriptors .FieldDescriptor | Describes a field of a message type. | Class | akka.protobuf.Descriptors | Akka |
| Descriptors .FieldDescriptor .JavaType | Returns the enum constant of this type with the specified name. | Class | akka.protobuf.Descriptors.FieldDescriptor | Akka |
| Descriptors .FieldDescriptor .Type | Class | akka.protobuf.Descriptors.FieldDescriptor | Akka | |
| Descriptors .FileDescriptor | Describes a . | Class | akka.protobuf.Descriptors | Akka |
| Descriptors .FileDescriptor .InternalDescriptorAssigner | This class should be used by generated code only. | Interface | akka.protobuf.Descriptors.FileDescriptor | Akka |
| Descriptors .MethodDescriptor | Describes one method within a service type. | Class | akka.protobuf.Descriptors | Akka |
| Descriptors .ServiceDescriptor | Describes a service type. | Class | akka.protobuf.Descriptors | Akka |