Exceptions are basically the events that disrupt the normal flow of the program. Exceptions can be either checked or unchecked. The main difference between the two is how they are handled by the Java compiler and how they affect the program flow.
Checked exceptions are exceptions that are caught by the Java compiler at compile-time. This means that if a method throws a checked exception, the compiler will force you to either handle it in the method or declare it to be thrown by the method. Checked exceptions indicate exceptional situations that can be handled by the code. Examples of checked exceptions include IOException, or FileNotFoundException.
Let's take a look at an example:
public void readFile(String fileName) throws IOException {
FileInputStream file = new FileInputStream(fileName);
// code to read from the file
file.close();
}
In this example, the readFile method throws an IOException if the file specified in the argument cannot be found or opened. The caller of the method must either handle the exception or declare that it throws the exception.
Unchecked exceptions, on the other hand, are not caught by the Java compiler. This means that the compiler will not force you to handle these exceptions. Unchecked exceptions indicate unexpected and severe problems that cannot be handled by the code. Examples of unchecked exceptions include NullPointerException or ArrayIndexOutOfBoundsException.
Here is an example of a method that throws an unchecked exception:
public void divide(int a, int b) {
if (b == 0) {
throw new ArithmeticException("Cannot divide by zero");
}
int result = a / b;
// code to handle the result
}
In this example, the divide method throws an ArithmeticException if the second argument is zero. The caller of the method does not have to handle the exception or declare that it throws the exception.
The main reason for the distinction between checked and unchecked exceptions is to provide the developer with more control over the program flow. Checked exceptions are used to indicate exceptional situations that can be handled by the code, while unchecked exceptions are used to indicate unexpected and severe problems that cannot be handled by the code.
It is important to note that checked exceptions can be converted to unchecked exceptions by wrapping them in an unchecked exception, such as RuntimeException. This is useful when a checked exception cannot be handled in the code, but the programmer still wants to signal the error to the calling code.
In conclusion, the distinction between checked and unchecked exceptions in Java provides the programmer with more control over the program flow and helps to write robust and maintainable code. It is important to understand the differences between the two and use them appropriately to write efficient and reliable code.