q from jiris.com

[JayaSiji Gopal]

What is wrong with the following code, if any?
(Select one correct answer)
--------------------------------------------------------------------------------

public class Test005
{
public static void main(String args[])
{
Thread.yield(); //1
Thread t = Thread.currentThread();
synchronized(t) { //2
t.notify(); //3
}
Object o = new Object();
System.out.println(null == o); //4
}
}


--------------------------------------------------------------------------------

A: The code does not compile due to line //1.
B: The code does not compile due to line //2.
C: The code does not compile due to line //3.
D: The code does not compile due to line //4.
E: There is nothing wrong with the code.

i answered d, since u r comparing null == o; but the correct answer is e.
can somebody plz explain.

[sanjeevmehra mehra]

I have not gone through the code yet my request is use code tag for posting the code, it is available just below Add Reply button, that would be helpful for all, thanks.

  
public class Test005
{ 
public static void main(String args[])
{
Thread.yield(); //1
Thread t = Thread.currentThread(); 

synchronized(t) { //2
t.notify(); //3
}
 

Object o = new Object(); 
System.out.println(null == o); //4 
} 
}

A: The code does not compile due to line //1.
B: The code does not compile due to line //2.
C: The code does not compile due to line //3.
D: The code does not compile due to line //4.
E: There is nothing wrong with the code.

i answered d, since u r comparing null == o; but the correct answer is e.
can somebody plz explain.

[Nicholas Cheung]

since u r comparing null == o

So, why I cannot do so?

Just like you will do this:

Object o = someFunctionCall();
if (o == null) {
   // do something
} else {
   // do some other thing
}

In such sense, either "true" or "false" will be printed to the standard output.

Nick

[sanjeevmehra mehra]

there is nothing wrong with line 4. it is comparing two values.
null == o, it will return either true or false.
== is comparison operator.