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Output question 13.
Java Interview Questions and Answers (part 4)
(Continued from previous question...)
73. Output question 13.
package o13_k15;
class Class2 {
void method2(String name) {
for (int x = 1; x <=2; x++) {
System.out.println(Thread.currentThread().getName());
}
}
}
public class MyClass implements Runnable {
Class2 obj2;
public static void main(String[] args) {
new MyClass().method1();
}
void method1() {
obj2 = new Class2();
new Thread(new MyClass()).start();
new Thread(new MyClass()).start();
}
public void run() {
obj2.method2(Thread.currentThread().getName());
}
}
Answer.
Program will face NullPointerException at Class2 obj2, we must make it static. As new Thread(new MyClass()).start(); creates thread on new instance of MyClass.
If Class2 obj2 is made static, than
Thread-0 and Thread-1 will be printed twice but in unpredictable order.
So, output will be different in subsequent executions,(as shown below)-
/*OUTPUT
Thread-1
Thread-1
Thread-0
Thread-0
*/
/*OUTPUT
Thread-0
Thread-1
Thread-1
Thread-0
*/
(Continued on next question...)
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