Recover in Miranda

Java provides a similar concept to recover called exception handling. Here’s how we can implement a similar behavior using try-catch blocks.

import java.util.function.Supplier;

public class ExceptionHandling {

    // This method throws an exception
    public static void mayThrow() {
        throw new RuntimeException("a problem");
    }

    // This method is similar to recover in Go
    public static void executeSafely(Runnable runnable) {
        try {
            runnable.run();
        } catch (Exception e) {
            System.out.println("Recovered. Error:\n " + e.getMessage());
        }
    }

    public static void main(String[] args) {
        executeSafely(() -> {
            mayThrow();
            // This code will not run because mayThrow throws an exception
            System.out.println("After mayThrow()");
        });
    }
}

In Java, we use try-catch blocks to handle exceptions. The executeSafely method is similar to the deferred function in the Go example. It takes a Runnable (which is similar to a function that doesn’t return anything) and executes it within a try-catch block.

The mayThrow method is equivalent to the mayPanic function in the Go example. It throws a RuntimeException instead of calling panic.

In the main method, we use a lambda expression to create a Runnable that calls mayThrow. This is wrapped in the executeSafely method, which will catch any exceptions thrown.

When you run this program, you’ll see:

$ javac ExceptionHandling.java
$ java ExceptionHandling
Recovered. Error:
 a problem

The “After mayThrow()” message is not printed because the exception is thrown before that line is reached, similar to how the panic in the Go example prevents further execution.

This approach provides a way to handle and recover from exceptions in Java, allowing your program to continue executing even when unexpected errors occur.