java lambda foreach update value non final variable

Question

I want to update the amount value, but it need to be final

int amount = 0;

// update value somewhere
amount = 12;

txs.forEach(p -> {
    p.setAmount(amount);
});

How to update all the txs with the same value?

Do you need the amount variable to be final? If no then explain a bit more. When a final variable is declared and assigned its value cannot be changed. So first declare the variable as final int amount; and do not assign any value. Assign at a place where you need. Or declare and assign at class level as a static constant. It all depends on your requirement. — TriS
– TriS, Commented Jul 12, 2021 at 9:18
You need to provide more context. You could simply write int amount = 12 in the first place, but I think you are already aware of that. So you need to show us where and how exactly you are planning to update the amount variable. — MC Emperor
– MC Emperor, Commented Jul 12, 2021 at 9:53

Rohaitas Tanoli · Accepted Answer · 2021-07-12 09:13:49Z

3

You can do it like this

int amount = 0;

// update value somewhere
amount = 12;

  // add this
final int final_amount = amount ;

txs.forEach(p -> {
    p.setAmount(final_amount);
});

answered Jul 12, 2021 at 9:13

Rohaitas Tanoli

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Elikill58 · Accepted Answer · 2021-07-12 09:09:40Z

2

An easy way to do it: Create a temporary variable like that:

int amount = 0;

// update value somewhere
amount = 12;

final int myFinalVariable = amount;

txs.forEach(p -> p.setAmount(myFinalVariable));

answered Jul 12, 2021 at 9:09

Elikill58

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