java_upgrade/src/test/java/lambdas/BinaryOperatorTest.java at main · alcmontejo/java_upgrade · GitHub

22 lines (18 loc) · 624 Bytes

package lambdas;

import org.junit.jupiter.api.Test;

import java.util.Arrays;

import java.util.List;

import java.util.Optional;

import java.util.function.BinaryOperator;

public class BinaryOperatorTest {

@Test

public void concatAsBinaryOperator() {

BinaryOperator<String> concat = String::concat;

// concat = (s, str) -> s.concat(str);

List<String> strings = Arrays.asList("this", "is", "a", "list", "of", "strings");

Optional<String> str = strings.stream()

//.filter(s -> false)

.reduce(concat);

System.out.println(str.orElse(""));

}

Expand file tree