Question

In most of the threading examples in Java, there is common use of a while(true) block like this:

while(true) {
 try {
  wait() 
 } catch (Exception ex) {
   /*do  something*/ 
 }
}

What is the purpose of using while (true) ? Under what kind of scenarios are they particularly useful?
Client/Server communications?

Thanks,
– Ivar

Answer 1

while(true) is useful if you want to do something all the time while your code is running and you don’t know how often you have to do it.

Client/Server Communication is one scenario. Other scenarios are animations of games or keeping some values always up to date.

A Thread is seperated from the other code, so your application would not hang by using while(true).

It is usefull to add an exit-flag to your while(true)-loop, so you can stop it if you want to.

Boolean isExit = false; //set this value to true when needed.
while(true) {
 try {
  if(isExist){
    break;
  }
  wait() 
 } catch (Exception ex) {
   /*do  something*/ 
 }
}