Heap memory in Java - Cheat Sheet & Quick Revision

overview

Recall & Review

beginner

What is heap memory in Java?

Heap memory is a part of memory where Java stores objects created during program execution. It is shared among all threads and managed by the Java Virtual Machine (JVM).

beginner

Where are Java objects stored during runtime?

Java objects are stored in the heap memory, which allows dynamic allocation and garbage collection.

intermediate

What role does the garbage collector play in heap memory?

The garbage collector automatically frees up heap memory by removing objects that are no longer referenced, helping to prevent memory leaks.

intermediate

How does heap memory differ from stack memory in Java?

Heap memory stores objects and is shared across threads, while stack memory stores method calls and local variables and is thread-specific.

advanced

What happens if the heap memory is full in a Java program?

If heap memory is full and no more objects can be allocated, the JVM throws an OutOfMemoryError, which usually crashes the program unless handled.

Where are Java objects stored during program execution?

A Heap memory

B Stack memory

C CPU registers

D Method area

What does the garbage collector do in heap memory?

A Allocates new objects

B Compiles Java code

C Manages stack frames

D Removes unreferenced objects

Which memory area is shared among all threads in Java?

A Program counter

B Stack memory

C Heap memory

D Native method stack

What error occurs if heap memory is exhausted?

A OutOfMemoryError

B NullPointerException

C StackOverflowError

D ClassNotFoundException

Which of the following is NOT stored in heap memory?

A Java objects

B Local variables

C Instance variables

D Arrays

Explain what heap memory is and why it is important in Java.

Describe the difference between heap memory and stack memory in Java.