有两个共享变量举个例子，领导安排活，发薪水，工人做活，拿工资；且假设活和工资足够工人，领导谈完项目才能拿到钱，工人做完工作才能拿工资

private int jobs;

private int salaries;

private final Object lockObjA = new Object();

private final Object lockObjB = new Object();

public void leader(int n) {
    synchronized (lockObjA) {
        this.jobs += n;
        // todo plan
        synchronized (lockObjB) {
            this.salaries += n;
            // todo deal
        }
    }
}

public void worker(int n) {
    synchronized (lockObjA) {
        this.jobs -= n;
        // todo job
        synchronized (lockObjB) {
            this.salaries -= n;
            // todo deal
        }
    }
}