Green Apple interview questions

Preview Questions

1. How is memory managed in Java?

   Java manages memory automatically so developers don’t have to handle it manually. When your program runs, Java stores all objects in the heap, while method calls and local variables are stored in the stack. The JVM also...

2. Differences between stack and heap memory.

   Stack memory is used for storing method calls, local variables, and function execution details. It works in a fast, organized Last In, First Out (LIFO) manner. Memory from the stack is automatically freed as soon as the...

3. Explain the difference between primitive and reference types.

   Primitive types store actual values directly in memory. Examples include int, float, char, and boolean. They hold simple, fixed-size data, and the variables contain the value itself — for example, an int x = 5 literally...

4. How do you implement multithreading?

   Multithreading is implemented by creating multiple threads that run tasks at the same time, helping programs work faster and stay responsive. In most languages like Java, this can be done by extending the Thread class,...

5. What are design patterns? Describe a few common ones.

   Design patterns are proven solutions to common problems that developers face when designing software. They are like templates that show the best way to structure your code so it becomes easier to understand, reuse, and...

6. What is an interface and how is it different from an abstract class?

   An interface is a blueprint that tells a class what methods it must implement, but it doesn’t contain any implementation details. It’s used to achieve full abstraction and multiple inheritance. An abstract class, on the...