Maven ArtifactNotFoundException troubleshooting

Question

Problem: I'm trying to get Google Protocol Buffers dependencies work. But with no result. Maven just can't pull any protocol buffers dependencies.

Question1: As I understand this dependency is absent in standard maven repositories, so I just need to indicate some extra repositories. Am I right?

Question2: If answer to the first question is YES, than how can I get the url of that extra repository? Here is the reference to maven dependency.

Error:

[ERROR] Plugin com.google.protobuf.tools:maven-protoc-plugin:0.3.2 or one of its dependencies could not be resolved: Failure to find com.google.protobuf.to
ols:maven-protoc-plugin:jar:0.3.2 in http://repo.maven.apache.org/maven2 was cached in the local repository, resolution will not be reattempted until the u
pdate interval of central has elapsed or updates are forced -> [Help 1]
org.apache.maven.plugin.PluginResolutionException: Plugin com.google.protobuf.tools:maven-protoc-plugin:0.3.2 or one of its dependencies could not be resol
ved: Failure to find com.google.protobuf.tools:maven-protoc-plugin:jar:0.3.2 in http://repo.maven.apache.org/maven2 was cached in the local repository, res
olution will not be reattempted until the update interval of central has elapsed or updates are forced
       .......
Caused by: org.eclipse.aether.resolution.ArtifactResolutionException: Failure to find com.google.protobuf.tools:maven-protoc-plugin:jar:0.3.2 in http://rep
o.maven.apache.org/maven2 was cached in the local repository, resolution will not be reattempted until the update interval of central has elapsed or update
s are forced

pom.xml:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>groupId</groupId>
    <artifactId>JavaSockets</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <dependency>
            <groupId>com.google.protobuf</groupId>
            <artifactId>protobuf-java</artifactId>
            <version>2.5.0</version>
        </dependency>
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.1</version>
                <configuration>
                    <source>1.7</source>
                    <target>1.7</target>
                </configuration>
            </plugin>
            <plugin>
                <groupId>com.google.protobuf.tools</groupId>
                <artifactId>maven-protoc-plugin</artifactId>
                <version>0.3.2</version>
                <configuration>
                    <protocExecutable>C:\Users\Clasik\Desktop\Java Sockets</protocExecutable>
                </configuration>
                <executions>
                    <execution>
                        <goals>
                            <goal>compile</goal>
                            <goal>testCompile</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>
</project>


        ......
Caused by: org.eclipse.aether.transfer.ArtifactNotFoundException: Failure to find com.google.protobuf.tools:maven-protoc-plugin:jar:0.3.2 in http://repo.ma
ven.apache.org/maven2 was cached in the local repository, resolution will not be reattempted until the update interval of central has elapsed or updates ar
e forced   
  ...............

Answer 1

The missing dependency is the maven-protoc-plugin, not protobuf-java. This plugin is not available in Maven Central.

According to it’s author you can add a self-hosted repository to the pom.xml:

<pluginRepositories>
    <pluginRepository>
        <id>protoc-plugin</id>
        <url>http://sergei-ivanov.github.com/maven-protoc-plugin/repo/releases/</url>
    </pluginRepository>
</pluginRepositories>

But I’m only getting a 404 here. So you can either contact the author or check out the sources and install the plugin manually in your local repository.

Answer 2

The solution is to add plugin repository:

<pluginRepositories>
    <pluginRepository>
        <id>dtrott</id>
        <url>http://maven.davidtrott.com/repository</url>
    </pluginRepository>
</pluginRepositories>

Answer 3

Older versions of this plugin are available from Bintray:

<pluginRepositories>
  <pluginRepository>
    <id>protoc-plugin</id>
    <url>https://dl.bintray.com/sergei-ivanov/maven</url>
  </pluginRepository>
</pluginRepositories>

I was able to get version 0.3.2 using this plugin repository which is linked to in the project readme