Ghosttrio

public class SharedResource {

    static class Resource implements Runnable {
        private int instanceField = 0;
        private static int staticField = 0;

        @Override
        public synchronized void run() {
            instanceField++;
            staticField++;

Ghosttrio

public class LocalVariable {

    static class MyThread extends Thread {
        @Override
        public void run() {
            int local = 0;
            local++;
            System.out.println("스레드 이름: " + Thread.currentThread().getName() + " 스레드의 지역 변수 : " + local);
        }
    }

Ghosttrio

chmod +x gradlew

Ghosttrio

/files/test.csv  //상대경로

classpath:/files/test.csv

Ghosttrio

List<String> list = resource.stream.collect(Collectors.toList());

// 더 간결함
List<String> list = resource.stream.toList();

Ghosttrio

List<String> list = stream.collect(Collectors.toList());

Set<String> set = stream.collect(Collectors.toSet());

Map<Integer, String> map = stream.collect(Collectors.toMap(String::length, Function.identity()));

Ghosttrio

<T, A, R> R collect(Collector<? super T, A, R> collector);

/**
  *  T: 스트림의 요소 타입
  *  A: 수집 과정에서 사용하는 내부 상태 타입
  *  R: 최종적으로 생성되는 결과 타입
  */

Ghosttrio

class Box<T>(val value: T)

class Dog : Animal()

open class Animal

fun addBoxContent(box: Box<Dog>) {
    val animalBox: Box<Animal> = box // 오류 발생
}

Ghosttrio

class Cat : Animal()
open class Animal

class Consumer<in T> {
    fun consume(item: T) {
        println(item)
    }
}

fun main() {

Ghosttrio

fun main() {
    val dogs: List<Dog> = listOf(Dog(), Dog())
    val animals: List<Animal> = dogs
    printList(animals)
}

open class Animal

class Dog : Animal()
class Cat : Animal()