Preventing a thread from executing

[Sreeram Desigan]

In a javabeat mock exam i found the following question
1 Which of the following can prevent a thread from executing?
(1) A call to its pause method
(2) A call to Thread.yield()
(3) Another thread is given higher priority
(4) A call to its halt() method

the answers are given as 2 and 3.
But according to me Thread.yield() method does not always prevent a thread from executing. It will move from executing state to ready state and the rest is platform dependent.
How can we say that 3 is a correct answer. Is't the priority implementation platform dependent.

[amod gole]

hi Sreeram Desigan ,

(2) A call to Thread.yield()

is correct



(3) Another thread is given higher priority

but i am not sure about this

[Asha Pathik]

Hi,

Thread.yield method does not guarantee that it will prevent the currently executing thread from execution.So, this is wrong.

I used to think that platform-dependent issues should not be considered as correct ans. as it changes from one system to another.

Someone else plz help on 2nd option.

Asha

[Tamara Lopez]

The question reads
"CAN prevent a thread from executing", and not WILL prevent a thread from executing.
Therefore option 2 is correct. It is not guaranteed, but it is possible, that yield takes a thread out of the running state.