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what is the answer

nikunj thakur
Ranch Hand

Joined: Sep 23, 2007
Posts: 47
class Mixer {
Mixer() { }
Mixer(Mixer m) { ml = m;}
Mixer m1;
public static void main(String[] args) {
Mixer m2 = new Mixer();
Mixer m3 = new Mixer(m2); m3.go();
Mixer m4 = m3.m1; m4.go();
Mixer m5 = m2.m1; m5.go();
}
void go() { System.out.print("hi "); }
}

What is the result?

hi

hi hi

hi hi hi

Compilation fails

hi, followed by an exception

hi hi, followed by an exception
answer is this

F is correct. The m2 object's m1 instance variable is never initialized, so when m5 tries to use it a NullPointerException is thrown.


but i am getting this

E:\kb>e:\jdk1.5.0\bin\javac Mixer.java
Mixer.java:3: cannot find symbol
symbol : variable ml
location: class Mixer
Mixer(Mixer m) { ml = m;}
^
1 error

E:\kb>

What is write
marc weber
Sheriff

Joined: Aug 31, 2004
Posts: 11343

Originally posted by nikunj thakur:
...
Mixer.java:3: cannot find symbol
symbol : variable ml
location: class Mixer...

You have a typo. In the third line, you typed "ml" using lowercase letters "M" and "L". But the lowercase 'L' should be the number '1' to match the variable declared on the following line...

Mixer(Mixer m) { m1 = m;}
Mixer m1;


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