Package io.a2a.spec

Class A2AError

java.lang.Object

java.lang.Throwable

java.lang.Exception

java.lang.RuntimeException

io.a2a.spec.A2AError

All Implemented Interfaces:

Event, Serializable

Direct Known Subclasses:

A2AProtocolError, InternalError, InvalidParamsError, InvalidRequestError, JSONParseError, MethodNotFoundError

public class A2AError
extends RuntimeException
implements Event

Marker interface for A2A Protocol error events.

This interface extends Event to allow errors to be transmitted as events in the A2A Protocol's event stream. All protocol-level errors implement this interface, enabling uniform error handling across both streaming and non-streaming communication.

A2A errors typically extend A2AError to provide JSON-RPC 2.0 compliant error responses with standard error codes, messages, and optional additional data.

Common implementations include:

• InvalidParamsError - Invalid method parameters
• InvalidRequestError - Malformed request
• MethodNotFoundError - Unknown method
• InternalError - Server-side error
• TaskNotFoundError - Task does not exist
• And others for specific protocol error conditions

See Also:

• for the base event interface
• for the base error implementation
• JSON-RPC 2.0 Error Object
• A2A Protocol Specification
• Serialized Form

Constructor Summary

Constructors

Constructor	Description
A2AError(Integer code, String message, @Nullable Object data)	Constructs a JSON-RPC error with the specified code, message, and optional data.

Method Summary

Modifier and Type	Method	Description
Integer	getCode()	Gets the numeric error code indicating the error type.
@Nullable Object	getData()	Gets additional information about the error.

Methods inherited from class java.lang.Throwable

addSuppressed, fillInStackTrace, getCause, getLocalizedMessage, getMessage, getStackTrace, getSuppressed, initCause, printStackTrace, printStackTrace, printStackTrace, setStackTrace, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Details

A2AError

public A2AError(Integer code,
 String message,
 @Nullable Object data)

Constructs a JSON-RPC error with the specified code, message, and optional data.

This constructor is used by Jackson for JSON deserialization.

Parameters:

code - the numeric error code (required, see JSON-RPC 2.0 spec for standard codes)

message - the human-readable error message (required)

data - additional error information, structure defined by the error code (optional)

Throws:

IllegalArgumentException - if code or message is null

Method Details

getCode

public Integer getCode()

Gets the numeric error code indicating the error type.

Standard JSON-RPC 2.0 error codes:

• -32700: Parse error
• -32600: Invalid Request
• -32601: Method not found
• -32602: Invalid params
• -32603: Internal error
• -32000 to -32099: Server error (implementation-defined)

Returns:

the error code

getData

public @Nullable Object getData()

Gets additional information about the error.

The structure and type of the data field is defined by the specific error code. It may contain detailed debugging information, validation errors, or other context-specific data to help diagnose the error.

Returns:

the error data, or null if not provided