Intellij IDEA 15: Unindexed remote maven repositories found

Question

I created a Java Gradle project in IntelliJ IDEA 15.0.3. But I am getting the following error.

Unindexed remote maven repositories found. Disable...
        The following repositories used in your gradle projects were not indexed yet: 
        http://repo1.maven.org/maven2
        If you want to use dependency completion for these repositories artifacts,
        Open Repositories List, select required repositories and press "Update" button (show balloon)

When I open the repositories list and click update, I am getting the following error

java.lang.RuntimeException: java.io.IOException: Transfer for nexus-maven-repository-index.properties failed

Answer 1

In your build.gradle repositories section replace mavencentral() with another mirror, like so:

repositories {
    maven {
        url "http://uk.maven.org/maven2"
    }
}

then when you get the "Unindexed remote maven repositories found" go to the repositories view and press update. that should do it

Answer 2

A possible (though not the only cause for this issue is, that you are behind a firewall that is blocking your connection). In this case you may need to configure a proxy server for Maven.

In my case it helped to just create a new file named settings.xml with the following contents and place it under C:\Users\<username>\.m2\ (or ~/.m2 on linux):

<settings>
  <proxies>
    <proxy>
      <id>HTTP proxy</id>
      <active>true</active>
      <protocol>http</protocol>
      <host>REPLACE_BY_IP_OR_HOSTNAME</host>
      <port>REPLACE_BY_PORT_NUMBER</port>
    </proxy>

    <proxy>
      <id>HTTPS proxy</id>
      <active>true</active>
      <protocol>https</protocol>
      <host>REPLACE_BY_IP_OR_HOSTNAME</host>
      <port>REPLACE_BY_PORT_NUMBER</port>
    </proxy>
 </proxies>
</settings>

Replace host and port for your specific environment.

Answer 3

Adding proxy settings to VM options worked. This answer helped me to set the proxy settings on IntelliJ for Maven