Re: Two stuck threads in synchronized method - at least it seems
like from a stack trace
Mike Schilling wrote:
Arne Vajh?j wrote:
Neil Coffey wrote:
Greg Stasica wrote:
public class DBQuery{
private static DBQuery dbQuery = null;
public static DBQuery getInstance()
{
if (dbQuery == null) {
dbQuery = new DBQuery();
}
return dbQuery;
}
You do know that this getInstance() method isn't thread-safe, don't
you?
At least he can get multiple DBQuery objects, but he should always
get a valid DBQuery reference back.
I don't think that's guaranteed. There is some possibility that he'll
get a DBQuery that is not fully initialized, since the JVM is within
its rights to reorder the assignment to dbQuery with the statements in
the constructor. (Disclaimer; that was true in the original JVM
memory model. I don't know if the current one changes that.)
I don't think the MM has changed regarding that.
And that could be a problem as well. Could be, because I don't
think we have seen the constructor.
Arne
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