session.setAttribute报错_java string contains方法

 if ((manager != null) && manager.getDistributable() &&
          !isAttributeDistributable(name, value))
            throw new IllegalArgumentException
                (sm.getString("standardSession.setAttribute.iae", name));

 protected boolean isAttributeDistributable(String name, Object value) {
        return value instanceof Serializable;
 }

 manager接口：
	
    /**
     * Return the distributable flag for the sessions supported by
     * this Manager.
     */
    public boolean getDistributable();
	
    /**
     * Set the distributable flag for the sessions supported by this
     * Manager.  If this flag is set, all user data objects added to
     * sessions associated with this manager must implement Serializable.
     *
     * @param distributable The new distributable flag
     */
    public void setDistributable(boolean distributable);