public void setGlobalSessionTimeout(long globalSessionTimeout) {
        this.globalSessionTimeout = globalSessionTimeout;
    }
Sets the system-wide default time in milliseconds that any session may remain idle before expiring. This
value is the main default for all sessions and may be overridden on a <em>per-session</em> basis by calling
{@code Subject.getSession().}{@link Session#setTimeout setTimeout(long)} if so desired.
<p/>
<ul>
<li>A negative return value means sessions never expire.</li>
<li>A non-negative return value (0 or greater) means session timeout will occur as expected.</li>
</ul>
<p/>
Unless overridden by calling this method, the default value is {@link #DEFAULT_GLOBAL_SESSION_TIMEOUT}.

@param globalSessionTimeout the time in milliseconds that any session may remain idle before expiring.
core/src/main/java/org/apache/shiro/session/mgt/AbstractSessionManager.java