nternal Server Error

java.lang.IllegalArgumentException: Failed to evaluate expression 'isMaster()'
  at org.springframework.security.access.expression.ExpressionUtils.evaluateAsBoolean(ExpressionUtils.java:30)
  at org.springframework.security.access.expression.method.ExpressionBasedPreInvocationAdvice.before(ExpressionBasedPreInvocationAdvice.java:59)
  at org.springframework.security.access.prepost.PreInvocationAuthorizationAdviceVoter.vote(PreInvocationAuthorizationAdviceVoter.java:72)
  at org.springframework.security.access.prepost.PreInvocationAuthorizationAdviceVoter.vote(PreInvocationAuthorizationAdviceVoter.java:40)

Fiber f = Fiber.execute( () -> {
    System.out.println("Good Morning!");
    readLock.lock();
    try {
        System.out.println("Good Afternoon");
    } finally {
        readLock.unlock();
    }
    System.out.println("Good Night");
});