eclipse-vertx/vert.x · error · IllegalArgumentException
HTTP/2 keepAliveTimeout must be >= 0
Error message
HTTP/2 keepAliveTimeout must be >= 0
What it means
Configuration validation in Http2ClientConfig.setKeepAliveTimeout: the Duration controlling how long an idle HTTP/2 connection stays in the pool before eviction must be non-negative (zero or null disables eviction). A negative Duration is rejected by the setter.
Source
Thrown at vertx-core/src/main/java/io/vertx/core/http/Http2ClientConfig.java:123
}
/**
* @return the keep alive timeout value in seconds for HTTP/2 connections
*/
public Duration getKeepAliveTimeout() {
return keepAliveTimeout;
}
/**
* <p>Set the keep alive timeout for HTTP/2 connections. This value determines how long a connection remains
* unused in the pool before being evicted and closed. A timeout of zero or {@code null} means there is no timeout.</p>
*
* @param keepAliveTimeout the timeout, in seconds
* @return a reference to this, so the API can be used fluently
*/
public Http2ClientConfig setKeepAliveTimeout(Duration keepAliveTimeout) {
if (keepAliveTimeout != null && (keepAliveTimeout.isNegative() || keepAliveTimeout.isZero())) {
throw new IllegalArgumentException("HTTP/2 keepAliveTimeout must be >= 0");
}
this.keepAliveTimeout = keepAliveTimeout;
return this;
}
/**
* @return the HTTP/2 upgrade maximum length of the aggregated content in bytes
*/
public int getUpgradeMaxContentLength() {
return upgradeMaxContentLength;
}
/**
* Set the HTTP/2 upgrade maximum length of the aggregated content in bytes.
* This is only taken into account when {@link Http2ClientConfig#isClearTextUpgradeWithPreflightRequest} is set to {@code false} (which is the default).
* When {@link Http2ClientConfig#isClearTextUpgradeWithPreflightRequest} is {@code true}, then the client makes a preflight OPTIONS request
* and the upgrade will not send a body, voiding the requirements.
*View on GitHub (pinned to fb308bd8c3)
Solutions
- Use a zero or positive Duration (or null) for the timeout
- Validate Duration configuration parsed from external sources
Defensive patterns
Strategy: validation
When it happens
Trigger: Thrown at vertx-core/src/main/java/io/vertx/core/http/Http2ClientConfig.java:123 when the library encounters an invalid state.
Common situations: See trigger scenarios.
Understand the failure class
- Timeouts: ETIMEDOUT, deadlines, and hung requests — what actually expires when a request times out.
AI-assisted analysis of eclipse-vertx/vert.x@fb308bd8c3 (2026-09-06).
Data as JSON: /api/errors/ee9ca3765b38f28e.
Report an issue: GitHub.