Package dev.relism.flash.http2

Class Http2Exception

java.lang.Object

java.lang.Throwable

java.lang.Exception

java.lang.RuntimeException

dev.relism.flash.http2.Http2Exception

All Implemented Interfaces:

Serializable

public final class Http2Exception
extends RuntimeException

A connection-level HTTP/2 error. Thrown anywhere a peer's frame, HPACK block, or SETTINGS value violates the protocol in a way that leaves the connection's state (the HPACK dynamic table, a flow-control window, the stream table) unrecoverable. single site: it sends GOAWAY with errorCode() and closes the connection. Compare Http2StreamException, whose scope is one stream and which results in RST_STREAM while the connection survives.

Deliberately does not extend IOException: the connection loop distinguishes a protocol violation (a decision Flash made about the peer's bytes) from a socket failure (the peer went away) by catching these as unrelated types. Conflating them would make it possible to accidentally treat a hostile peer's malformed frame as a harmless disconnect, or vice versa.

Why stack traces are disabled

This exception is thrown on the connection's hot rejection path — a single malformed byte from a hostile or buggy peer can trigger it, and under a scripted attack that can happen many times per second across many connections. JVM stack trace capture (fillInStackTrace) is by far the most expensive part of constructing a Throwable, and it buys nothing here: the call site is exactly where errorCode() says it is, and the debug message already names the specific violation. The 4-argument RuntimeException constructor disables both suppression and stack-trace writing.

Preallocated singletons

For the common, message-less rejections (frame validation failures, HPACK structural errors) this class exposes shared singleton instances. Reusing one instance across threads and across many throws is safe only because the instance carries no per-throw mutable state and writable-stack-trace is disabled — nothing about a throw mutates the exception object.

See Also:

• Serialized Form

Field Summary

Fields

Modifier and Type	Field	Description
static final Http2Exception	COMPRESSION_ERROR
static final Http2Exception	FLOW_CONTROL_ERROR
static final Http2Exception	FRAME_SIZE_ERROR
static final Http2Exception	INTERNAL_ERROR
static final Http2Exception	PROTOCOL_ERROR
static final Http2Exception	SETTINGS_TIMEOUT

Method Summary

Modifier and Type	Method	Description
Http2ErrorCode	errorCode()	The RFC 9113 §7 error code to send in the GOAWAY frame.
static Http2Exception	of(Http2ErrorCode code, String message)	Builds a connection error carrying a caller-supplied debug message.

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

Field Details

PROTOCOL_ERROR

public static final Http2Exception PROTOCOL_ERROR

FRAME_SIZE_ERROR

public static final Http2Exception FRAME_SIZE_ERROR

FLOW_CONTROL_ERROR

public static final Http2Exception FLOW_CONTROL_ERROR

COMPRESSION_ERROR

public static final Http2Exception COMPRESSION_ERROR

INTERNAL_ERROR

public static final Http2Exception INTERNAL_ERROR

SETTINGS_TIMEOUT

public static final Http2Exception SETTINGS_TIMEOUT

Method Details

errorCode

public Http2ErrorCode errorCode()

The RFC 9113 §7 error code to send in the GOAWAY frame.

of

public static Http2Exception of(Http2ErrorCode code,
 String message)

Builds a connection error carrying a caller-supplied debug message. Allocates a new message carries information specific to this occurrence (e.g. the offending stream id or a decoded value); use one of the preallocated singletons below when it does not.