Loans API

URL:

http://localhost:8090/api/loans

Health Check

GET /sayHello

Test GET API request with Loans Controller

http://localhost:8090/api/loans/sayHello

Create A Loan

POST ?mobileNumber=1234567890

Create a new loan passing name, email, and mobileNumber

Request:

{
    "name": "Joe Bloggs",
    "email": "joe@gmail.com",
    "mobileNumber": "1234567890"    
}

Response: 201 Created:

{
    "statusCode": "201",
    "statusMsg": "Loan created successfully"
}

Loan already exists:

Response: 400 Bad Request

{
    "apiPath": "uri=/api/loans",
    "errorCode": "BAD_REQUEST",
    "errorMessage": "Loan already registered with given mobileNumber 1234567890",
    "errortime": "2026-04-03T01:33:44.4108084"
}

Fetch Loan Details

GET ?mobileNumber=1234567890

Fetch the loan details by phone number

Response: 200 OK

{
    "mobileNumber": "1234567890",
    "loanNumber": "100347363839",
    "loanType": "Home Loan",
    "totalLoan": 100000,
    "amountPaid": 0,
    "outstandingAmount": 100000
}

Mobile number does not exist in the the database:

Response: 404 Not Found

{
    "apiPath": "uri=/api/loans",
    "errorCode": "NOT_FOUND",
    "errorMessage": "Loan not found with the given input data mobileNumber : '1234567899'",
    "errortime": "2026-04-03T01:32:08.959885"
}

Update Loan Details

PUT

Update the customer details

Request:

{
    "mobileNumber": "1234567890",
    "loanNumber": "100347363839",
    "loanType": "Car Loan",
    "totalLoan": 100000,
    "amountPaid": 2000,
    "outstandingAmount": 98000
}

Response: 200 OK

{
    "statusCode": "200",
    "statusMsg": "Request processed successfully"
}

Loan number does not exist in the the database:

Response: 404 Not Found

{
    "apiPath": "uri=/api/loans",
    "errorCode": "NOT_FOUND",
    "errorMessage": "Loan not found with the given input data LoanNumber : '100008437212'",
    "errortime": "2026-04-03T02:27:31.6457924"
}

Fetch Updated Loan Details

GET ?mobileNumber=1234567890

Fetch the updated loan details

Response: 200 OK

{
    "mobileNumber": "1234567890",
    "loanNumber": "100347363839",
    "loanType": "Car Loan",
    "totalLoan": 100000,
    "amountPaid": 2000,
    "outstandingAmount": 98000
}

Delete Loan

DELETE ?mobileNumber=1234567890

Delete loan by mobileNumber

Response: 200 OK

{
    "statusCode": "200",
    "statusMsg": "Request processed successfully"
}

Loan doesn't exist or already deleted Response 404 Not Found

{
    "apiPath": "uri=/api/loans",
    "errorCode": "NOT_FOUND",
    "errorMessage": "Loan not found with the given input data mobileNumber : '1234567890'",
    "errortime": "2026-04-03T02:41:46.0353513"
}

Input Validation

LoansDto

Input validation handled in LoansDto

@Data
public class LoansDto {
    @NotEmpty(message = "MobileNumber cannot be null or empty")
    @Pattern(regexp = "(^$|[0-9]{10})", message = "Mobile Number must be 10 digits")
    private String mobileNumber;

    @NotEmpty(message = "LoanNumber cannot be null or empty")
    @Pattern(regexp = "(^$|[0-9]{12})", message = "LoanNumber must be 12 digits")
    private String loanNumber;

    @NotEmpty(message = "LaonType cannot be null or empty")
    private String loanType;

    @Positive(message = "Total loan amount should be greater than zero")
    private Integer totalLoan;

    @PositiveOrZero(message = "Total loan amount paid should be equal or greater than zero")
    private Integer amountPaid;

    @PositiveOrZero(message = "Total outstanding amount should be equal or greater than zero")
    private Integer outstandingAmount;
}

GET

GET ?mobileNumber=123456789

Fetch phone number with invalid length (must be 10 digits)

Response: 500 Internal Server Error

{
    "apiPath": "uri=/api/loans",
    "errorCode": "INTERNAL_SERVER_ERROR",
    "errorMessage": "fetchAccountDetails.mobileNumber: Mobile number must be 10 digits",
    "errortime": "2026-04-03T01:48:31.3337033"
}

GET ?mobileNumber=1234567895

Fetch phone number, Loan Not Found
Mobile number does not exist in the database

Response: 404 Not Found

{
    "apiPath": "uri=/api/loans",
    "errorCode": "NOT_FOUND",
    "errorMessage": "Loan not found with the given input data mobileNumber : '1234567895'",
    "errortime": "2026-04-03T01:50:32.548013"
}

PUT

PUT

Update input negative amount validation

Request:

{
    "mobileNumber": "1234567890",
    "loanNumber": "10000843722",
    "loanType": "Home Loan",
    "totalLoan": -100000,
    "amountPaid": -2000,
    "outstandingAmount": -98000
}

Response: 200 OK

{
    "amountPaid": "Total loan amount paid should be equal or greater than zero",
    "outstandingAmount": "Total outstanding amount should be equal or greater than zero",
    "totalLoan": "Total loan amount should be greater than zero",
    "loanNumber": "LoanNumber must be 12 digits"
}

PUT

Update input phone number validation

Request:

{
    "mobileNumber": "123456790",
    "loanNumber": "100008437221",
    "loanType": "Home Loan",
    "totalLoan": 100000,
    "amountPaid": 2000,
    "outstandingAmount": 98000
}

Response: 200 OK

{
    "mobileNumber": "Mobile Number must be 10 digits"
}

Delete

DELETE ?mobileNumber=12345678

Delete loan with invalid mobile number length

Response: 500 Internal Server Error

{
    "apiPath": "uri=/api/loans",
    "errorCode": "INTERNAL_SERVER_ERROR",
    "errorMessage": "deleteAccountDetails.mobileNumber: Mobile number must be 10 digits",
    "errortime": "2026-04-03T02:43:04.2164548"
}

Delete

DELETE ?mobileNumber=12345678

Delete loan with mobile number not found

Response: 404 Not Found

{
    "apiPath": "uri=/api/loans",
    "errorCode": "NOT_FOUND",
    "errorMessage": "Loan not found with the given input data mobileNumber : '9876543210'",
    "errortime": "2026-04-03T02:46:17.1251248"
}