Panic in Karel

import java.io.File;
import java.io.IOException;

public class ExceptionExample {
    public static void main(String[] args) {
        // We'll use exceptions throughout this site to check for
        // unexpected errors. This is the only program on the
        // site designed to throw an exception.
        throw new RuntimeException("a problem");

        // A common use of exceptions is to abort if a method
        // returns an error that we don't know how to
        // (or want to) handle. Here's an example of
        // throwing an exception if we get an unexpected error when creating a new file.
        try {
            File file = new File("/tmp/file");
            if (!file.createNewFile()) {
                throw new IOException("Failed to create file");
            }
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }
}

Running this program will cause it to throw an exception, print an error message and stack trace, and exit with a non-zero status.

When the first exception in main is thrown, the program exits without reaching the rest of the code. If you’d like to see the program try to create a temp file, comment out the first exception.

$ java ExceptionExample
Exception in thread "main" java.lang.RuntimeException: a problem
    at ExceptionExample.main(ExceptionExample.java:9)

Note that unlike some languages which use return values for handling of many errors, in Java it is idiomatic to use exceptions for handling exceptional situations.

In Java, we use try-catch blocks to handle exceptions. The throws keyword is used to declare that a method might throw an exception. The throw keyword is used to explicitly throw an exception.

The concept of panic in Go is similar to throwing an unchecked exception in Java. Both are used for situations that should not occur during normal operation and typically lead to program termination if not handled.

Remember that in Java, checked exceptions (subclasses of Exception but not RuntimeException) must be either caught or declared in the method signature, while unchecked exceptions (subclasses of RuntimeException or Error) don’t have this requirement.