java8 stream not showing the expected output - java-8

Question

Iterate the list and create multiple objects.
Below is the sample json:
"accountRequest": [
{
"accountId": "10EIIP",
"custId": "11EE",
"custName": "XYZ",
"comments": null,
"status": "active",
"linkedDetails": [
{
"custCode": "001",
"startOn": "2023-01-01",
"loanType": "auto"
},
{
"custCode": "002",
"startOn": "2023-01-15",
"loanType": "home"
},
{
"custCode": "003",
"startOn": "2023-02-10",
"loanType": "home"
}
]
}
]
Account.java
class Account{
#JsonProperty("accountId")
private Long accountId;
#JsonProperty("custId")
private String custId;
//custName, comments, status
private String custCode;
private LocalDate startOn;
private String loanType;
}
I need to create list of "Account" by storing each of linkedDetails. The sample code below does not store accountId, custId, custName, comments, status in the "Account" object. Expected output is to create List of size 3..
List<Account> accountList = new ArrayList<>();
List<AccountRequest> accountRequestList = request.getAccountRequest();
accountRequestList.get(0).getLinkedDetails().forEach(linkedDetails -> {
Account account = new Account();
//need to set accountId, custId, custName, comments, status in each account object
account.setCustCode(linkedDetails.getCustCode());
account.setStartOn(linkedDetails.getStartOn());
account.setLoanType(linkedDetails.getLoanType());
accountList.add(account);
});
Expected Output :
"accountList": [
{
"accountId": "10EIIP",
"custId": "11EE",
"custName": "XYZ",
"comments": null,
"status": "active",
"custCode": "001",
"startOn": "2023-01-01",
"loanType": "auto"
},
{
"accountId": "10EIIP",
"custId": "11EE",
"custName": "XYZ",
"comments": null,
"status": "active",
"custCode": "002",
"startOn": "2023-01-15",
"loanType": "home"
},
{
"accountId": "10EIIP",
"custId": "11EE",
"custName": "XYZ",
"comments": null,
"status": "active",
"custCode": "003",
"startOn": "2023-02-10",
"loanType": "home"
}
]

Answer 1

Instead of creating a mutable list and modifying it in a foreach you should directly collect to the accountList:
List<AccountRequest> accountRequestList = request.getAccountRequest();
List<Account> accountList = accountRequestList.get(0).getLinkedDetails().stream().map(linkedDetails -> {
Account account = new Account();
//need to set accountId, custId, custName, comments, status in each account object
account.setCustCode(linkedDetails.getCustCode());
account.setStartOn(linkedDetails.getStartOn());
account.setLoanType(linkedDetails.getLoanType());
return account;
}).collect(Collectors.toList());