What Are Runtime Exceptions

In Java, runtime exceptions are exceptions that occur during the execution of a program. Unlike checked exceptions, which the compiler requires you to handle or declare, runtime exceptions are unchecked, meaning that the compiler does not enforce any handling mechanism.

Runtime exceptions are typically caused by issues that cannot be easily predicted or prevented by the programmer, such as dividing by zero, accessing an array index that is out of bounds, or attempting to convert a string to a numeric value when the string is not a valid number.

Some common examples of runtime exceptions in Java include:

1. ArithmeticException: Thrown when an arithmetic operation, such as division by zero, is performed.
2. ArrayIndexOutOfBoundsException: Thrown when trying to access an array element with an index outside the valid range.
3. NullPointerException: Thrown when attempting to access an object or invoke a method on an object that is null.
4. ClassCastException: Thrown when attempting to cast an object to a type that it is not an instance of.
5. NumberFormatException: Thrown when trying to convert a string to a numeric type, but the string does not represent a valid number.

It’s important to note that while these exceptions are unchecked, it’s still good practice to handle them appropriately to improve the robustness and reliability of your code. However, Java does not force you to catch or declare runtime exceptions explicitly.