class Sample{
    private Object _lock=new Object();
    public void someMethod(){
        synchronized(_lock){
            doSomething();
        }
    }
}

class Sample{
    private ISchedulingRule _lock=new SomeSchedulingRule();
    public void someMethod(){
        try{
            Job.getManager().beginRule(_lock);
            doSomething();
        }finally{
            Job.getManager().endRule(_lock);
        }
    }
}