Can we override thread start method?

Can we override a start() method in Java? Yes, we can override the start() method of a Thread class in Java. We must call the super. start() method to create a new thread and need to call run() method in that newly created thread.

What happens if we override start method?

Whenever we override start() method then our start() method will be executed just like a normal method call and new thread wont be created. We can override start/run method of Thread class because it is not final. But it is not recommended to override start() method, otherwise it ruins multi-threading concept.

What happens if we invoke start method on dead thread?

A dead state can not be started again. If a start() method is invoked on a dead thread a runtime exception will occur.

Why must you override the run () method in your thread class?

It is highly recommended to override run() method because it improves the performance of the system. If we don't override Thread class run() method in our defined thread then Thread class run() method will be executed and we will not get any output because Thread class run() is with an empty implementation.

What will happen if we don't override the thread run () method in a child class?

Answer: If we don't override run() method, compiler will not flash any error and it will execute run() method of Thread class that has empty implemented, So, there will be no output for this thread.

# 129 Overriding of Thread class start() method | how to override thread.start()? | Java|RedSysTech

Can we overload run method in multithreading?

Yes , it possible to overload run ( ) method while using Threads in java .

Can we start a thread twice in Java?

No. After starting a thread, it can never be started again. If you does so, an IllegalThreadStateException is thrown. In such case, thread will run once but for second time, it will throw exception.

What would happen if you replace the Start () method with the run () method in the below code?

If run() method is called directly instead of start() method in Java code, run() method will be treated as a normal overridden method of the thread class (or runnable interface). This run method will be executed with in the context of the current thread not in a new thread.

Is it possible to call the run () method directly to start a new thread?

No, you can not directly call run method to start a thread. You need to call start method to create a new thread. If you call run method directly , it won't create a new thread and it will be in same stack as main.

Can a dead thread be started again?

Once a thread enters dead state it cannot be restarted.

What is difference between starting thread with Run () and start () method?

start method of thread class is implemented as when it is called a new Thread is created and code inside run() method is executed in that new Thread. While if run method is executed directly than no new Thread is created and code inside run() will execute on current Thread and no multi-threading will take place.

How do I run one thread after another?

To execute threads one after another it needs to be synchronized. wait notify notifyAll is useful. This is the famous interview question for the beginners, Write a program that creates 3 threads and prints alternate values in sequence.

What happens if we don't override Run method?

Answer: If we don't override run() method, compiler will not flash any error and it will execute run() method of Thread class that has empty implemented, So, there will be no output for this thread.

What is maximum thread priority in Java?

All Java threads have a priority in the range 1-10. priority ie. priority by default is 5. Whenever a new Java thread is created it has the same priority as the thread which created it.

What notifyAll () method does?

notifyAll. Wakes up all threads that are waiting on this object's monitor. A thread waits on an object's monitor by calling one of the wait methods. The awakened threads will not be able to proceed until the current thread relinquishes the lock on this object.

Can we call run method twice?

The run method is called twice. One call is by calling start() in the MyRunnable constructor; this is executed in the separate thread. That prints "MyRunnable". However, you also call run directly in main , which is executed in the main thread.

Why do we call start method in thread instead of run?

Calling start () will start a new Thread and calling run() method does not start a new Thread. If you call start() method on Thread, Java Virtual Machine will call run() method and two threads will run concurrently now - Current Thread and Other Thread or Runnable implementation.

What is the difference between notify () and notifyAll ()?

In case of multiThreading notify() method sends the notification to only one thread among the multiple waiting threads which are waiting for lock. While notifyAll() methods in the same context sends the notification to all waiting threads instead of single one thread.

What if run () is invoked on a thread twice?

No, we cannot start Thread again, doing so will throw runtimeException java. lang. IllegalThreadStateException. > The reason is once run() method is executed by Thread, it goes into dead state.

Is daemon a thread?

A Daemon thread is a background service thread which runs as a low priority thread and performs background operations like garbage collection. JVM exits if only daemon threads are remaining. The setDaemon() method of the Thread class is used to mark/set a particular thread as either a daemon thread or a user thread.

Does multithreading use polling method?

The benefit of Java s multithreading is that the main loop/polling mechanism is eliminated. One thread can pause without stopping other parts of your program. Threads can be in several states like running, ready, suspended, blocked, resumed.

Why wait is used in synchronized block?

wait method tells the current thread (thread which is executing code inside a synchronized method or block) to give up monitor and go to waiting state. notify method wakes up a single thread that is waiting on this object's monitor.

Can we override wait method in Java?

Ans. wait and notify are declared final in object class and hence cannot be overridden.

Can I implement my own start () method?

Answer: Yes, we can override start() method of thread in Java, the same way we override any other methods. for example, In below, custom thread class MyThread, both start() method and run() method have been overridden.