Panic in Miranda

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 and uncomment the file creation code.

$ 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 exceptional circumstances and error handling.

In Java, we use try-catch blocks to handle exceptions, and we can throw exceptions using the throw keyword. The RuntimeException used in this example is an unchecked exception, which doesn’t require explicit handling. However, for checked exceptions like IOException, we must either catch them or declare that our method throws them.

The equivalent of Go’s panic in Java is throwing an unchecked exception. While Go’s panic is typically used for unrecoverable errors, Java exceptions can be caught and handled, allowing for more flexible error management.