Try monad example (requires com.jasongoodwin.monads)

gistfile1.java

import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;

import com.jasongoodwin.monads.Try;

public class TryTest {
	
	public static String doStuff(String s) {
		if(s.startsWith("a")) {
			throw new IllegalArgumentException("Incorrect string: "+s);
		}
		return s.trim();
	}

	public static void main(String[] args) {
		List<String> input = Arrays.asList("aaa", "b", "abc  ", "  qqq  ");
		
		Map<Boolean, List<Try<String>>> result = input.stream()
				.map(Try::successful).map(t -> t.map(TryTest::doStuff))
				.collect(Collectors.partitioningBy(Try::isSuccess));
		System.out.println(result.get(true).stream().map(t -> t.orElse(null))
		                .collect(Collectors.joining(",")));
		result.get(false).stream().forEach(t -> t.onFailure(System.out::println));
	}
}