public <V> V execute(Callable<V> callable) throws ExecutionException {
        Callable<V> associated = associateWith(callable);
        try {
            return associated.call();
        } catch (Throwable t) {
            throw new ExecutionException(t);
        }
    }
Returns {@code true} if this Subject is allowed to create sessions, {@code false} otherwise.

@return {@code true} if this Subject is allowed to create sessions, {@code false} otherwise.
@since 1.2
core/src/main/java/org/apache/shiro/subject/support/DelegatingSubject.java