Debugging and error handling are essential parts of programming, including in Processing. Debugging involves identifying and fixing errors in the code while error handling involves anticipating and handling errors that may occur during program execution.

Debugging in Processing involves using various techniques to find and fix errors in the code. This can be done by using print statements to check variable values or using the built-in debugging tools like breakpoints to pause the program's execution at a specific point to evaluate the code. Using a debugger can help locate the error's source, and the programmer can then make the necessary changes to fix it.

Error handling in Processing is essential because errors can occur at any point during the program's execution. Error handling involves anticipating and catching errors and then handling those errors appropriately. This can be done using try-catch blocks, which attempt to execute a block of code and catch any exceptions that arise. Error handling can help improve the application's stability by preventing errors from causing program crashes or other problems.

In summary, debugging and error handling are two critical skills for any programmer, including in Processing. By learning and mastering these skills, programmers can create more robust and reliable programs that are less likely to fail due to errors.