刚换了MBP，三天上手开发，逼自己学习了一把，用起来还是很舒服的，下面开始i记录一个开发中碰到的问题～
idea 开发中为什么不能下载maven source code 了呢？
这样 让我怎么学习源码进步呢？
先贴下报错信息吧：
java.lang.RuntimeException: Cannot reconnect.
at org.jetbrains.idea.maven.server.RemoteObjectWrapper.perform(RemoteObjectWrapper.java:82)
at org.jetbrains.idea.maven.server.MavenEmbedderWrapper.customizeForResolve(MavenEmbedderWrapper.java:52)
at org.jetbrains.idea.maven.project.MavenProjectResolver.downloadSourcesAndJavadocs(MavenProjectResolver.java:253)
at org.jetbrains.idea.maven.project.MavenProjectsProcessorArtifactsDownloadingTask.perform(MavenProjectsProcessorArtifactsDownloadingTask.java:40)
at org.jetbrains.idea.maven.project.MavenProjectsProcessor.doProcessPendingTasks(MavenProjectsProcessor.java:145)
at org.jetbrains.idea.maven.project.MavenProjectsProcessor.access$000(MavenProjectsProcessor.java:36)
at org.jetbrains.idea.maven.project.MavenProjectsProcessor$1.run(MavenProjectsProcessor.java:114)
at org.jetbrains.idea.maven.utils.MavenUtil.lambda$runInBackground$5(MavenUtil.java:500)
at com.intellij.util.RunnableCallable.call(RunnableCallable.java:20)
at com.intellij.util.RunnableCallable.call(RunnableCallable.java:11)
at com.intellij.openapi.application.impl.ApplicationImpl$1.call(ApplicationImpl.java:268)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
at java.base/java.util.concurrent.Executors$PrivilegedThreadFactory$1$1.run(Executors.java:668)
at java.base/java.util.concurrent.Executors$PrivilegedThreadFactory$1$1.run(Executors.java:665)
at java.base/java.security.AccessController.doPrivileged(Native Method)
at java.base/java.util.concurrent.Executors$PrivilegedThreadFactory$1.run(Executors.java:665)
at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: java.rmi.ConnectException: Connection refused to host: 127.0.0.1; nested exception is:
java.net.ConnectException: Connection refused (Connection refused)
at java.rmi/sun.rmi.transport.tcp.TCPEndpoint.newSocket(TCPEndpoint.java:623)
at java.rmi/sun.rmi.transport.tcp.TCPChannel.createConnection(TCPChannel.java:209)
at java.rmi/sun.rmi.transport.tcp.TCPChannel.newConnection(TCPChannel.java:196)
at java.rmi/sun.rmi.server.UnicastRef.invoke(UnicastRef.java:132)
at java.rmi/java.rmi.server.RemoteObjectInvocationHandler.invokeRemoteMethod(RemoteObjectInvocationHandler.java:217)
at java.rmi/java.rmi.server.RemoteObjectInvocationHandler.invoke(RemoteObjectInvocationHandler.java:162)
at com.sun.proxy.$Proxy135.createEmbedder(Unknown Source)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.base/java.lang.reflect.Method.invoke(Method.java:566)
at com.intellij.execution.rmi.RemoteUtil.invokeRemote(RemoteUtil.java:155)
at com.intellij.execution.rmi.RemoteUtil.access$400(RemoteUtil.java:25)
at com.intellij.execution.rmi.RemoteUtil$1.lambda$invoke$0(RemoteUtil.java:139)
at com.intellij.openapi.util.ClassLoaderUtil.computeWithClassLoader(ClassLoaderUtil.java:31)
at com.intellij.execution.rmi.RemoteUtil.executeWithClassLoader(RemoteUtil.java:207)
at com.intellij.execution.rmi.RemoteUtil$1.invoke(RemoteUtil.java:139)
at com.sun.proxy.$Proxy135.createEmbedder(Unknown Source)
at org.jetbrains.idea.maven.server.MavenServerConnector.createEmbedder(MavenServerConnector.java:187)
at org.jetbrains.idea.maven.server.MavenServerManager$2.create(MavenServerManager.java:397)
at org.jetbrains.idea.maven.server.MavenServerManager$2.create(MavenServerManager.java:385)
at org.jetbrains.idea.maven.server.RemoteObjectWrapper.getOrCreateWrappee(RemoteObjectWrapper.java:41)
at org.jetbrains.idea.maven.server.MavenEmbedderWrapper.doCustomize(MavenEmbedderWrapper.java:93)
at org.jetbrains.idea.maven.server.MavenEmbedderWrapper.lambda$customizeForResolve$0(MavenEmbedderWrapper.java:53)
at org.jetbrains.idea.maven.server.RemoteObjectWrapper.perform(RemoteObjectWrapper.java:76)
... 18 more
科学上网也没找到解决方案，网上最多的就是说
ping localhost 看看是不是 127.0.0.1
没什么问题啊 ，哥 ping 出来是本机地址啊
今天终于被我尝试除了解决方案
给 Java 添加 Maven 库的 https 证书
maven 运行的虚拟机增加参数
maven -> importing VM options 设置如下参数
-Xmx768m -Dmaven.wagon.http.ssl.insecure=true -Dmaven.wagon.http.ssl.allowall=true -Djava.net.preferIPv4Stack=true
