Which code practice can cause ANR in Android apps?

int[] arr = new int[3];

System.out.println(arr[3]);

What happens?

A food delivery app extends features from a base User class to Customer and DeliveryPartner. This is an example of:

In a project, the same method login() behaves differently for Admin and User roles. Which concept is used?

Why do product-based companies emphasize debugging and optimization skills during interviews?

Replacing $$O(n^2)$$ algorithm with $$O(n \log n)$$ primarily results in:

An app feature shows noticeable delay due to nested loops. Which improvement has the highest impact on performance?

While debugging, a developer wants to trace the sequence of method calls that led to a crash. Which tool is most useful?

A destroyed Activity remains in memory due to a static reference. What long-term effect can this cause?

A complex UI uses multiple nested layouts and suffers from slow rendering. Which refactoring strategy is most effective?

class Test {

Test() {

this(10);

System.out.print("Default "); }

Test(int x) {

System.out.print("Param "); }}

public class Main {

public static void main(String[] args)

{ new Test(); }}

What is the output?

An app crashes when dividing a number by zero during execution. This is an example of:

A mobile app occasionally becomes unresponsive during API calls. Which design decision best prevents this issue in production?

A developer restricts direct access to sensitive user data and exposes only controlled update methods. What is the primary benefit?

A discount calculation logic is written as:

if price > 500:

discount = price * 0.10

else:

discount = price * 0.05

During sale, customers with price = 500 complain about wrong discount. What is the issue?

A variable is declared but assigned an incompatible data type in a strongly typed language. At which stage is this issue detected?

A shopping app calculates discounts correctly for most users but applies incorrect values during seasonal offers. The code runs without crashing. What best explains this issue?

A fintech company redesigns its app so that new payment methods can be added without modifying existing code. Which design principle is primarily applied?

A reference variable of type Payment points to objects of UPI, Card, and Wallet. At runtime, the correct pay() method is invoked. This behavior depends on: