Re: simultaneous function calls

Lew <>
Wed, 05 Sep 2007 09:37:27 -0400
korcs schrieb:

I have an application, where several threaded-objects (each with an
own thread), are using the methods of a single (non-threaded) object.

phi wrote:

2 calls at the same time should not be a problem, if you synchronize the
using the "single (non-threaded) object" as monitor.

There is no such thing as a "non-threaded" object.

Since the object in question is used by many threads simultaneously, any
association with it of the term "non-threaded" is erroneous in this case.

The object must be written to be thread-safe.

phi wrote:

This could be a synchronizing problem. But it's difficult to tell
without source code.

It's easy to tell without the source code: it's a synchronization problem.

To give the Threads a higher priority, use the threads "setPriority()"

Not reliable, and not the answer to the OP's real problem.

Rule of thumb: At any given time, the highest priority thread is running. However, this is not guaranteed. The thread scheduler may choose to run a lower priority thread to avoid starvation. For this reason, use priority only to affect scheduling policy for efficiency purposes.
Do not rely on thread priority for algorithm correctness.

The tutorial that Sabine recommended is a necessary beginning. Study /Java
Concurrency in Practice/ by Brian Goetz, et al., for more mastery.

Thread programming is a subtle and dangerous art.


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