Object lifecycle in Java - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the object lifecycle in Java?

The object lifecycle is the series of stages an object goes through: creation, usage, and destruction (garbage collection).

beginner

Which Java keyword is used to create a new object?

The new keyword is used to create a new object in Java.

intermediate

What happens when an object is no longer referenced in Java?

When no references point to an object, it becomes eligible for garbage collection, meaning Java can remove it to free memory.

advanced

What is the role of the finalize() method in the object lifecycle?

The finalize() method is called by the garbage collector before an object is destroyed, but its use is discouraged in modern Java and deprecated since Java 9.

intermediate

Explain the difference between stack and heap in the context of object lifecycle.

The stack stores references and method calls, while the heap stores the actual objects. Objects live in the heap during their lifecycle.

Which stage is NOT part of the Java object lifecycle?

A Compilation

B Usage

C Destruction

D Creation

Compilation is a step before running the program and is not part of the object lifecycle.

What keyword do you use to create a new object in Java?

A make

B create

C new

D init

The new keyword creates a new object instance.

When does Java remove an object from memory?

A When the object is created

B When the object is no longer referenced

C When the program starts

D When the object is declared

Java removes objects when they have no references and are eligible for garbage collection.

Where are Java objects stored during their lifecycle?

A Heap

B Register

C Stack

D Cache

Objects are stored in the heap memory during their lifecycle.

What is the purpose of the finalize() method?

A To create an object

B To start the program

C To initialize variables

D To clean up before object destruction

The finalize() method is called before garbage collection to clean up resources, but its use is discouraged and deprecated in modern Java.

Describe the stages of the object lifecycle in Java and what happens at each stage.

Think about how an object is made, used, and then removed.

Explain how Java manages memory for objects during their lifecycle.

Consider where objects live and how Java frees memory.