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Code comes up with main as the thread name. :confused: Even though the main thread is still running dosen't Thread.currentThread(); see the context in which it is being called?
Code:class T extends Thread{
public T(String tname){
super(tname);
}
public void run(){
Thread t = Thread.currentThread();
String tname = t.getName();
boolean isalive = t.isAlive();
for(int i = 1; i <= 10; ++i){
System.out.println(tname + " is alive ?" + " : " + isalive);
}
}
}
How are you calling the thread? Calling isAlive on the current thread is quite futile, you know...
The thread is being started from the main method. :ehh: I don't know why calling isAlive() would be futile.
The action of querying the current thread's alive status requires the thread to be alive. Which implies that isAlive will invariably return true.
I'd still like to see the creation code.
I don't quite follow. Why would the thread being alive be a requirment to call isAlive()? If the run() method is finished executing then isAlive() simply returns false.Quote:
Posted by CornedBee
The action of querying the current thread's alive status requires the thread to be alive.
As long as a thread is executing, it's alive. And if it's not executing, it cannot call isAlive() on any thread object, most definitely not the one returned by currentThread(), which represents itself. It is therefore a requirement that a thread is executing if it is to call isAlive() on the value returned by currentThread(), thus implying that isAlive() will return true.
I don't know about that. I beg to differ. ;) So let me ask you this. If a thread is created, set off, run() finishes executing then isAlive() is called what exception is thrown?Quote:
Posted by CornedBee
As long as a thread is executing, it's alive. And if it's not executing, it cannot call isAlive() on any thread object, most definitely not the one returned by currentThread(), which represents itself. It is therefore a requirement that a thread is executing if it is to call isAlive() on the value returned by currentThread(), thus implying that isAlive() will return true.
WILL a thread references another thread have the exact same name?
If you simply put Thread.currentThread().getName() in the system.out that will give you the correct name...but then again that doesn't makes sense if the the reference thread won't return that name either.
If it's an alias it should since you are simply referring to the same object.Quote:
WILL a thread references another thread have the exact same name?
What the hell are you talking about? Once run() finishes executing, that thread will not call isAlive() anymore!Quote:
Originally Posted by Dilenger4
Another thread might then call isAlive() and it will return false. But in your snippet, you're calling isAlive() on the return value of currentThread(). This means it's the current thread, and that the current thread is alive.
Here is what you wrote. "As long as a thread is executing, it's alive. And if it's not executing, it cannot call isAlive() on any thread object"
That sounds like you are saying just because a thread is not alive that isAlive() cannot be called on it.
CB i understand that the last quote i posted refers to my code and is not a generalization because if it were you would be incorrect. Also as for my code you are pointing out the obvious and besides we are getting off base. The real question is why Thread.currentThread() refers to the main thread and not the seperate thread that was created after the main thread is spawned.
No, you're confusing caller and called in my statement. The thread which calls isAlive() must be alive. The thread on whose object isAlive() is called need not be alive.Quote:
Originally Posted by Dilenger4
I'm still correct, but you're right, we're getting off-track. So I'm going to ask you for the thread creation code for the third time :)
Because as it is, this code gives me the correct result:
The output:Code:class T extends Thread{
public T(String tname){
super(tname);
}
public void run(){
Thread t = Thread.currentThread();
String tname = t.getName();
boolean isalive = t.isAlive();
for(int i = 1; i <= 10; ++i){
System.out.println(tname + " is alive ?" + " : " + isalive);
}
}
public static void main(String[] bla) {
new T("hello").start();
}
}
Code:hello is alive ? : true
hello is alive ? : true
hello is alive ? : true
hello is alive ? : true
hello is alive ? : true
hello is alive ? : true
hello is alive ? : true
hello is alive ? : true
hello is alive ? : true
hello is alive ? : true
You mean the second. :lol: j/kQuote:
Posted by CornedBee
So I'm going to ask you for the thread creation code for the third time :)
Correct. We were just having trouble with semantics. :DQuote:
Posted by CornedBee
The thread which calls isAlive() must be alive. The thread on whose object isAlive() is called need not be alive.
The results that you come up with are expected. What i am concerned about is the thread name not the status. System.out.println() prints main for me and hello for you.
Here is what i have.
Code:public class ThreadTest{
public static void main(String[] args){
T t = new T("T Thread");
threadStatus(t.isAlive(),t.getName());
t.run();
}
public static void threadStatus(boolean isalive, String tname){
String status = isalive ? "is alive" : " is not alive";
System.out.println(tname +""+ status);
}
}
class T extends Thread{
public T(String tname){
super(tname);
}
public void run(){
Thread t = Thread.currentThread();
String tname = t.getName();
boolean isalive = t.isAlive();
for(int i = 1; i <= 10; ++i){
System.out.println(tname + " is alive ?" + " : " + isalive);
}
}
}
I figured out why the thread name was main. It was becasue i was calling run() instead of calling start() on the thread. :eek2:
Exactly what I thought after running my test.