assertNull and assertNotNull in JUnit - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to check if the object is null using JUnit.

JUnit

[1](myObject);

Drag options to blanks, or click blank then click option'

AassertEquals

BassertNotNull

CassertNull

DassertTrue

Attempts:

3 left

💡 Hint

Common Mistakes

Using assertNotNull instead of assertNull.

Using assertEquals which requires two parameters.

The assertNull method checks if the given object is null. It passes if the object is null.

2fill in blank

medium

Complete the code to check if the object is not null using JUnit.

JUnit

[1](user);

Drag options to blanks, or click blank then click option'

AassertNotNull

BassertFalse

CassertNull

DassertSame

Attempts:

3 left

💡 Hint

Common Mistakes

Using assertNull instead of assertNotNull.

Using assertFalse which expects a boolean condition.

The assertNotNull method checks if the object is not null. It passes if the object exists.

3fill in blank

hard

Fix the error in the assertion to check that the variable is null.

JUnit

[1](expectedValue, actualValue);

Drag options to blanks, or click blank then click option'

AassertNull

BassertNotNull

CassertEquals

DassertTrue

Attempts:

3 left

💡 Hint

Common Mistakes

Using assertNull with two parameters causes a compile error.

Confusing assertNull with assertEquals.

The assertNull method takes only one argument. Using two arguments causes an error. Replace with assertNull and pass only the object to check.

4fill in blank

hard

Fill both blanks to assert that the object is not null and provide a failure message.

JUnit

[1]("Object should not be null", [2]);

Drag options to blanks, or click blank then click option'

AassertNotNull

BassertNull

CmyObject

Dnull

Attempts:

3 left

💡 Hint

Common Mistakes

Using assertNull instead of assertNotNull.

Passing null instead of the object variable.

The assertNotNull method can take a message and the object to check. The message shows if the test fails. The object must be the second argument.

5fill in blank

hard

Fill all three blanks to assert that the user object is null with a custom message.

JUnit

[1]("User must be null", [2]); // Check user
// Next, assert that the session is not null
[3](session);

Drag options to blanks, or click blank then click option'

AassertNull

Buser

CassertNotNull

Dsession

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up assertNull and assertNotNull.

Passing wrong variables to assertions.

Use assertNull with a message and the user object to check it is null. Then use assertNotNull to check the session is not null.