Java 8 Lambda function that throws exception?

Question

I know how to create a reference to a method that has a String parameter and returns an int, it\'s:

Function         


        

Answer 1

I'm the author of a tiny lib with some generic magic to throw any Java Exception anywhere without the need of catching them nor wrapping them into RuntimeException.

Usage: unchecked(() -> methodThrowingCheckedException())

public class UncheckedExceptions {

    /**
     * throws {@code exception} as unchecked exception, without wrapping exception.
     *
     * @return will never return anything, return type is set to {@code exception} only to be able to write throw unchecked(exception)
     * @throws T {@code exception} as unchecked exception
     */
    @SuppressWarnings("unchecked")
    public static  T unchecked(Exception exception) throws T {
        throw (T) exception;
    }


    @FunctionalInterface
    public interface UncheckedFunction {
        R call() throws Exception;
    }

    /**
     * Executes given function,
     * catches and rethrows checked exceptions as unchecked exceptions, without wrapping exception.
     *
     * @return result of function
     * @see #unchecked(Exception)
     */
    public static  R unchecked(UncheckedFunction function) {
        try {
            return function.call();
        } catch (Exception e) {
            throw unchecked(e);
        }
    }


    @FunctionalInterface
    public interface UncheckedMethod {
        void call() throws Exception;
    }

    /**
     * Executes given method,
     * catches and rethrows checked exceptions as unchecked exceptions, without wrapping exception.
     *
     * @see #unchecked(Exception)
     */
    public static void unchecked(UncheckedMethod method) {
        try {
            method.call();
        } catch (Exception e) {
            throw unchecked(e);
        }
    }
}

source: https://github.com/qoomon/unchecked-exceptions-java