Custom exception classes in Spring Boot - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a custom exception class that extends RuntimeException.

Spring Boot

public class MyException extends [1] {
    public MyException(String message) {
        super(message);
    }
}

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AException

BRuntimeException

CThrowable

DError

Attempts:

3 left

💡 Hint

Common Mistakes

Extending Exception instead of RuntimeException causes checked exceptions.

Extending Throwable or Error is not recommended for custom exceptions.

The custom exception class should extend RuntimeException to create an unchecked exception.

2fill in blank

medium

Complete the code to throw the custom exception with a message.

Spring Boot

if (user == null) {
    throw new [1]("User not found");
}

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AException

BIllegalArgumentException

CMyException

DRuntimeException

Attempts:

3 left

💡 Hint

Common Mistakes

Throwing a generic Exception instead of the custom one.

Using a different exception class that does not match the custom exception.

Throw the custom exception MyException to indicate a specific error condition.

3fill in blank

hard

Fix the error in the custom exception constructor to properly pass the message to the superclass.

Spring Boot

public class MyException extends RuntimeException {
    public MyException(String message) {
        [1](message);
    }
}

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Asuper

Bthis

Cthrow

Dreturn

Attempts:

3 left

💡 Hint

Common Mistakes

Using this(message) instead of super(message).

Trying to use throw or return inside constructor.

The constructor must call super(message) to pass the message to the RuntimeException constructor.

4fill in blank

hard

Fill both blanks to create a custom exception with a default message and a constructor that accepts a message.

Spring Boot

public class [1] extends RuntimeException {
    public [2]() {
        super("Default error message");
    }
}

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AMyException

BCustomException

Attempts:

3 left

💡 Hint

Common Mistakes

Using different names for class and constructor.

Using a generic name that does not match the class.

The class name and constructor name must match. Here, both are MyException.

5fill in blank

hard

Fill all three blanks to define a custom exception with two constructors: one default and one with a message.

Spring Boot

public class [1] extends RuntimeException {
    public [2]() {
        super("Default message");
    }
    public [3](String message) {
        super(message);
    }
}

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ACustomError

BCustomException

CMyException

DAppException

Attempts:

3 left

💡 Hint

Common Mistakes

Using different names for constructors and class.

Mixing class names from other examples.

All constructors and the class must share the same name, here CustomException.