alibaba/arthas · error · SessionNotFoundException

Session not found: {sessionId}

Error message

Session not found: {sessionId}

What it means

Thrown as SessionNotFoundException by getCurrentSession when a non-blank sessionId was supplied but sessionManager.getSession(sessionId) returned null — i.e. no session exists with that id (it was never created, expired, or was explicitly invalidated).

Source

Thrown at core/src/main/java/com/taobao/arthas/core/command/CommandExecutorImpl.java:70

    }

    public Session getCurrentSession(String sessionId, boolean oneTimeIsAllowed) {
        if (sessionId == null || sessionId.trim().isEmpty()) {
            if (!oneTimeIsAllowed) {
                throw new SessionNotFoundException("SessionId is required for this operation");
            }

            Session session = sessionManager.createSession();
            if (session == null) {
                throw new SessionNotFoundException("Failed to create temporary session");
            }
            session.put(ONETIME_SESSION_KEY, new Object());
            logger.debug("Created one-time session {}", session.getSessionId());
            return session;
        } else {
            Session session = sessionManager.getSession(sessionId);
            if (session == null) {
                throw new SessionNotFoundException("Session not found: " + sessionId);
            }
            sessionManager.updateAccessTime(session);
            logger.debug("Using existing session {}", sessionId);
            return session;
        }
    }

    /**
     * 内部同步执行方法，统一处理认证和session管理
     * 
     * @param commandLine 命令行
     * @param timeout 超时时间
     * @param sessionId session ID，如果为null则创建临时session
     * @param authSubject 认证主体，如果不为null则应用到session
     * @param userId 用户 ID，用于统计上报
     * @return 执行结果
     */
    @Override

View on GitHub (pinned to 21cf2e9ba5)

Solutions

1. Catch SessionNotFoundException, then create a fresh session and retry with the new id.
2. Verify the id was issued by this Arthas instance and is still within its TTL.
3. Refresh/reopen sessions after long idle periods or after Arthas restarts.

Example fix

// before
Session s = executor.getCurrentSession(oldSid, false);

// after
Session s;
try {
    s = executor.getCurrentSession(oldSid, false);
} catch (SessionNotFoundException e) {
    s = sessionManager.createSession();
    oldSid = s.getSessionId();
}

Session s = sessionManager.getSession(sessionId);
if (s == null) { sessionId = sessionManager.createSession().getSessionId(); }

try {
    Session s = executor.getCurrentSession(sessionId, false);
} catch (SessionNotFoundException e) {
    sessionId = sessionManager.createSession().getSessionId();
    // retry with the new id
}

When it happens

Trigger: Call getCurrentSession(nonBlankId, ...) with an id the manager does not recognize: a stale id from a previous run, an expired id past TTL, a mistyped/forged id, or an id from a session that was closed.

Common situations: Client holds a sessionId across a restart/reconnect of Arthas; session TTL elapsed between calls; multiple Arthas instances and the client hit the wrong one; typo or truncated id.

Related errors

• SessionId is required for this operation
• -32602
• Required parameter '{paramName}' cannot be empty
• {iface} missing newInstance method
• {iface} is not an interface

AI-assisted analysis of alibaba/arthas@21cf2e9ba5 (2026-08-14). Data as JSON: /api/errors/31dfc6a707d48155. Report an issue: GitHub.