Why custom exceptions are needed in Java - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a custom exception class named MyException.

Java

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

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AError

BException

CThrowable

DRuntimeException

Attempts:

3 left

💡 Hint

Common Mistakes

Extending Error or Throwable directly is not common for custom exceptions.

Custom exceptions usually extend Exception to create checked exceptions.

2fill in blank

medium

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

Java

if (value < 0) {
    throw new [1]("Value cannot be negative");
}

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AIllegalArgumentException

BException

CMyException

DRuntimeException

Attempts:

3 left

💡 Hint

Common Mistakes

Throwing generic exceptions like Exception or RuntimeException instead of the custom one.

We throw the custom exception MyException to signal a specific error.

3fill in blank

hard

Fix the error in the method signature to declare that it throws MyException.

Java

public void checkValue(int value) [1] {
    if (value < 0) {
        throw new MyException("Negative value");
    }
}

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Athrow Exception

Bthrow MyException

Cthrows Exception

Dthrows MyException

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'throw' instead of 'throws' in the method signature.

The method must declare throws MyException to indicate it can throw this checked exception.

4fill in blank

hard

Fill both blanks to catch the custom exception and print its message.

Java

try {
    checkValue(-5);
} catch ([1] e) {
    System.out.println(e.[2]());
}

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AMyException

BgetMessage

CprintStackTrace

DException

Attempts:

3 left

💡 Hint

Common Mistakes

Catching generic Exception instead of MyException.

Using printStackTrace() instead of getMessage() for printing.

Catch the custom exception MyException and use getMessage() to print the error message.

5fill in blank

hard

Fill all three blanks to create a custom exception, throw it, and catch it properly.

Java

public class [1] extends Exception {
    public [1](String msg) {
        super(msg);
    }
}

public class Test {
    public static void main(String[] args) {
        try {
            throw new [2]("Error happened");
        } catch ([3] e) {
            System.out.println(e.getMessage());
        }
    }
}

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ACustomException

DMyException

Attempts:

3 left

💡 Hint

Common Mistakes

Using different names for the exception class in declaration, throw, and catch.

Define a custom exception class CustomException, throw it, and catch it by the same class name.