Java Thread Implementation: Identifying the Incorrect Code Snippet

Jerry wants to implement a thread object. Which of the following code snippets is incorrect?

A

class InfoManage extends Thread {
public static void main(String[] args) {

InfoManage im = new InfoManage();
im.start();
}
}

B

class InfoManage implements Runnable {
@Override
public void run() {
System.out.println('running');
}
public static void main(String[] args) {
InfoManage im = new InfoManage();
im.start();
}
}

C

class InfoManage {
public static void main(String[] args) {
Thread t = new Thread(new Runnable() {
@Override
public void run() {
System.out.println('running');
}
});
t.start();
}
}

D

class InfoManage implements Runnable {
@Override
public void run() {
System.out.println('running');
public static void main(String[] args) {
InfoManage im = new InfoManage();
Thread t = new Thread(im);
t.start();
}
}

Answer: D

The run() method in option D has a syntax error. There is a missing semicolon after the t.start() statement, and the main method is incorrectly placed inside the run() method.

Explanation:

• Option A: This code snippet correctly extends the Thread class and uses the start() method to initiate the thread.
• Option B: This code snippet implements the Runnable interface and creates a separate Thread object using the Runnable instance, which is then started with the start() method.
• Option C: This code snippet demonstrates the use of an anonymous inner class implementing Runnable to create a thread.
• Option D: This snippet contains the syntax error mentioned above, making it the incorrect implementation. The main method should be defined outside the run() method. The semicolon after t.start() is also missing.