CODEWITHSUNDEEP
javaclone
user1876712
user1876712

Reputation: 113

Why the clone() method does not work properly?

I have a 2-dimensional vector called 'link_occur_nodup' which contains data as [[5, 2, 1, 1], [2, 1, 1]]. Now, if i try to do

Vector<Vector<Integer>> temp=(Vector<Vector<Integer>>) link_occur_nodup.clone();
    temp.elementAt(0).set(1, 50);
    System.out.println(temp+" "+link_occur_nodup);

The output is: [[5, 50, 1, 1], [2, 1, 1]] [[5, 50, 1, 1], [2, 1, 1]] Iam wondering why does the value being changed in both of the vectors?. Instead it has to be only in the 'temp' vector. Can someone explain please?

Upvotes: 1

Views: 240

Answers (2)

Louis Wasserman
Louis Wasserman

Reputation: 198014

clone only does a shallow copy: so you get a new Vector with references to the same objects as the original. This is the expected behavior.

If you want different behavior, you'll need to manually copy the inner Vectors yourself. (This is one of the many reasons why the use of clone is ill-advised.)

Upvotes: 12

SLaks
SLaks

Reputation: 887225

You've cloned the outer Vector.

Your cloned vector contains the same inner vectors as the original one.

Upvotes: 3

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