private static boolean hasSignal0() {
        try {
            Class.forName("sun.misc.Signal");
            return true;
        } catch (final Throwable t) {
            if (LOG.isWarnEnabled()) {
                LOG.warn("sun.misc.Signal: unavailable.", t);
            }
        }
        return false;
    }
Registers user signal handlers.

@param signalName a signal name
@param handlers   user signal handlers
@return true if support on current platform
jraft-core/src/main/java/com/alipay/sofa/jraft/util/SignalHelper.java