Java. Object instance changes weirdly

Question

class Test {
    static int p;
    Test(int x) {
        p=x;
    }
}

class Mtest
{
    public static void main(String args[])
    {
        Test c[] = new Test [100];
        for(int i=0; i<5; i++) {
            c[i]=new Test(i);
        }

        for (int i=0; i<5;i++) {
            System.out.println(c[i].p);         
        }
}

OUTPUT: 4 4 4 4 4

What kind of sorcery is this? shouldnt it give me 0,1,2,3,4??

Remove the static keyword from declaration of p, and see the magic. — Rohit Jain
– Rohit Jain, Commented Jan 20, 2014 at 19:01

Jigar Joshi · Accepted Answer · 2014-01-20 19:01:58Z

4

You are using static field

static int p;

which is shared across class (not per instance)

if you want it per Object, remove static from declaration

answered Jan 20, 2014 at 19:01

Jigar Joshi

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1 Comment

Peter Lawrey Over a year ago

There is only one p variable so it can have only one value, the last one.

Filipp Voronov · Accepted Answer · 2014-01-20 19:02:18Z

0

Because p is static, i.e. field of the class, not of an object. So p is shared between all instances of class test. You should remove static from field declaration to achieve your result expectations.

answered Jan 20, 2014 at 19:02

Filipp Voronov

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Comments

kmera · Accepted Answer · 2014-01-20 19:02:39Z

0

You declared p as static. Remove it and it should word fine. Plus format your code following the java guidelines, it makes it much more readable.

answered Jan 20, 2014 at 19:02

kmera

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Submersed · Accepted Answer · 2014-01-20 19:02:43Z

0

Change static int p; to int p -> You're using class variables instead of instance variables.

answered Jan 20, 2014 at 19:02

Submersed

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