Intellij Idea Maven 存储库都在“更新”字段中显示“错误”

Question

I am trying to run a couple of Maven projects. Mainly I want to use methods from one (local) project within another (local) project.

I understand I need to get Maven to add the one project to the local .m2 repository.

However when I try and update the local repository it just says "error". It also says that when I try and update the remote repositories and Maven is saying that a number of the plugins (eg org.apache.maven.plugins:maven-javadoc-plugin:3.0 ) are not found.

So I guess I'm missing a set up step for Idea. However I don't know what that is and I can't find it.

I've tried invalidating the cache and restarting as per a couple of answers on SO which has not helped. The project builds fine at the command line.

The idea.log has in response to be attempting to update the local.m2 database:

2021-04-12 11:24:38,002 [254387512]   WARN -      #org.jetbrains.idea.maven - Failed to update Maven indices for: [local] /Users/jontyn/.m2/repository 
java.lang.RuntimeException: Cannot reconnect.
    at org.jetbrains.idea.maven.server.RemoteObjectWrapper.perform(RemoteObjectWrapper.java:82)
    at org.jetbrains.idea.maven.server.MavenIndexerWrapper.createIndex(MavenIndexerWrapper.java:50)
    at org.jetbrains.idea.maven.indices.MavenIndex.createContext(MavenIndex.java:384)
    at org.jetbrains.idea.maven.indices.MavenIndex.updateOrRepair(MavenIndex.java:337)
    at org.jetbrains.idea.maven.indices.MavenIndices.updateOrRepair(MavenIndices.java:128)
    at org.jetbrains.idea.maven.indices.MavenIndicesManager.doUpdateIndices(MavenIndicesManager.java:292)
    at org.jetbrains.idea.maven.indices.MavenIndicesManager$3.run(MavenIndicesManager.java:256)
    at com.intellij.openapi.progress.impl.CoreProgressManager$TaskRunnable.run(CoreProgressManager.java:962)
    at com.intellij.openapi.progress.impl.CoreProgressManager.lambda$runProcessWithProgressAsync$5(CoreProgressManager.java:472)
    at com.intellij.openapi.progress.impl.ProgressRunner.lambda$submit$3(ProgressRunner.java:235)
    at com.intellij.openapi.progress.impl.CoreProgressManager.lambda$runProcess$2(CoreProgressManager.java:178)
    at com.intellij.openapi.progress.impl.CoreProgressManager.registerIndicatorAndRun(CoreProgressManager.java:658)
    at com.intellij.openapi.progress.impl.CoreProgressManager.executeProcessUnderProgress(CoreProgressManager.java:610)
    at com.intellij.openapi.progress.impl.ProgressManagerImpl.executeProcessUnderProgress(ProgressManagerImpl.java:65)
    at com.intellij.openapi.progress.impl.CoreProgressManager.runProcess(CoreProgressManager.java:165)
    at com.intellij.openapi.progress.impl.ProgressRunner.lambda$submit$4(ProgressRunner.java:235)
    at java.base/java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1700)
    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$1.run(Executors.java:665)
    at java.base/java.lang.Thread.run(Thread.java:834)
Caused by: java.rmi.ConnectException: Connection refused to host: 127.0.0.1; nested exception is: 
    java.net.ConnectException: Connection refused (Connection refused)
    at java.rmi/sun.rmi.transport.tcp.TCPEndpoint.newSocket(TCPEndpoint.java:623)
    at java.rmi/sun.rmi.transport.tcp.TCPChannel.createConnection(TCPChannel.java:209)
    at java.rmi/sun.rmi.transport.tcp.TCPChannel.newConnection(TCPChannel.java:196)
    at java.rmi/sun.rmi.server.UnicastRef.invoke(UnicastRef.java:132)
    at java.rmi/java.rmi.server.RemoteObjectInvocationHandler.invokeRemoteMethod(RemoteObjectInvocationHandler.java:217)
    at java.rmi/java.rmi.server.RemoteObjectInvocationHandler.invoke(RemoteObjectInvocationHandler.java:162)
    at com.sun.proxy.$Proxy121.createIndexer(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:150)
    at com.intellij.execution.rmi.RemoteUtil.access$400(RemoteUtil.java:21)
    at com.intellij.execution.rmi.RemoteUtil$1.lambda$invoke$0(RemoteUtil.java:134)
    at com.intellij.openapi.util.ClassLoaderUtil.computeWithClassLoader(ClassLoaderUtil.java:31)
    at com.intellij.execution.rmi.RemoteUtil.executeWithClassLoader(RemoteUtil.java:202)
    at com.intellij.execution.rmi.RemoteUtil$1.invoke(RemoteUtil.java:134)
    at com.sun.proxy.$Proxy121.createIndexer(Unknown Source)
    at org.jetbrains.idea.maven.server.MavenServerConnectorImpl.createIndexer(MavenServerConnectorImpl.java:197)
    at org.jetbrains.idea.maven.server.MavenServerManager$4.create(MavenServerManager.java:381)
    at org.jetbrains.idea.maven.server.MavenServerManager$4.create(MavenServerManager.java:377)
    at org.jetbrains.idea.maven.server.RemoteObjectWrapper.getOrCreateWrappee(RemoteObjectWrapper.java:41)
    at org.jetbrains.idea.maven.server.MavenIndexerWrapper.getRemoteId(MavenIndexerWrapper.java:136)
    at org.jetbrains.idea.maven.server.MavenIndexerWrapper.lambda$createIndex$0(MavenIndexerWrapper.java:50)
    at org.jetbrains.idea.maven.server.RemoteObjectWrapper.perform(RemoteObjectWrapper.java:76)
    ... 23 more
Caused by: java.net.ConnectException: Connection refused (Connection refused)
    at java.base/java.net.PlainSocketImpl.socketConnect(Native Method)
    at java.base/java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:399)
    at java.base/java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:242)
    at java.base/java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:224)
    at java.base/java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
    at java.base/java.net.Socket.connect(Socket.java:609)
    at java.base/java.net.Socket.connect(Socket.java:558)
    at java.base/java.net.Socket.<init>(Socket.java:454)
    at java.base/java.net.Socket.<init>(Socket.java:231)
    at com.intellij.execution.rmi.RemoteServer$1.createSocket(RemoteServer.java:122)
    at java.rmi/sun.rmi.transport.tcp.TCPEndpoint.newSocket(TCPEndpoint.java:617)
    ... 47 more

Answer 1

Idea needs to be connected to a network in order to access the local.m2 repository?

IDE launches the Maven server process when importing the Maven based project or downloading Maven indexes. For communication with this process IDE uses loopback interface. See Unable to import Maven project, import fails with error: Cannot reconnect related documentation:

There could be several causes why localhost is not accessible:

• DNS misconfiguration The 127.0.0.1 is the standard address for IPv4 loopback traffic and the localhost name must resolve to 127.0.0.1 IPv4 address. If it is not - the error will occur.

• Antivirus or firewall blocks connections to localhost

• the IDE bug when this error intermittently happens: https://youtrack.jetbrains.com/issue/IDEA-263673 It usually will work on the next attempt or project re-open.