当我将它添加到我的项目父 pom 时：
<dependency>
<groupId>org.springframework.cloud</groupId>
<artifactId>spring-cloud-starter-netflix-eureka-client</artifactId>
<version>2.1.3.RELEASE</version>
</dependency>
项目运行失败，如下所示：
2019-11-11 00:12:56.158 INFO 78547 --- [ restartedMain] .e.DevToolsPropertyDefaultsPostProcessor : Devtools property defaults active! Set 'spring.devtools.add-properties' to 'false' to disable
2019-11-11 00:12:56.421 INFO 78547 --- [ restartedMain] trationDelegate$BeanPostProcessorChecker : Bean 'org.springframework.cloud.autoconfigure.ConfigurationPropertiesRebinderAutoConfiguration' of type [org.springframework.cloud.autoconfigure.ConfigurationPropertiesRebinderAutoConfiguration$$EnhancerBySpringCGLIB$$684316fc] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying)
2019-11-11 00:12:56.436 WARN 78547 --- [ restartedMain] s.c.a.AnnotationConfigApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.BeanCreationException: Error creating bean with …好吧,我遇到了一个惊人的问题......
public class Test {
private boolean[] state = new boolean[]{false, false};
public void createThread() {
Thread th1 = new Thread(() -> {
try {
System.out.println("1");
Thread.sleep(2000);
state[0]=true;
} catch (InterruptedException e) {
e.printStackTrace();
}
});
Thread th2 = new Thread(() -> {
try {
System.out.println("2");
Thread.sleep(2000);
state[1] = true;
} catch (InterruptedException e) {
e.printStackTrace();
}
});
th1.start();
th2.start();
}
public static void main(String args[]) throws InterruptedException {
Test test = new Test();
test.createThread();
while (true) {
// Thread.sleep(1); …List<Integer> integers = Arrays.asList(1, 2);
List<Integer> integers2 = Arrays.asList(1, 2);
Collection<Integer> integers3 = Collections.unmodifiableCollection(integers);
Collections.unmodifiableCollection(integers2);
integers3.add(3);
integers2.add(3);
我知道执行integers3.add()会抛出 UnsupportedOperationException，但 integers2 没有改变实例。我查看了 Collections.unmodifiableCollection(Collection ..) 的源代码，但是 integers2 的实现也从 AbstractList 抛出了 UnsupportedOperationException。为什么是这样？