title: How to fix this gradle dependency resolution error?
body: <p>I am new to gradle and I am trying to use it for an existing java project.</p>
  
  <p>I have created settings.gradle file in my root directory:</p>
  
  <pre><code>include ':datamodel'
  include ':active'
  include ':client'
  include ':zero'
  include ':toall'
  </code></pre>
  
  <p>and build.gradle</p>
  
  <pre><code>// Top-level build file where you can add configuration options common to all sub-projects/modules.
  buildscript {
      repositories {
          mavenCentral()
      }
      dependencies {
      }
  }
  </code></pre>
  
  <p>The build.gradle in datamodel looks like this:</p>
  
  <pre><code>apply plugin: 'java'
  sourceSets {
      main.java.srcDirs = ['src/main/java']
      main.resources.srcDirs = ['src/main/java']
      test.java.srcDirs = ['tests/java']
      test.resources.srcDirs = ['tests/resources']
  }
  
  dependencies {
      compile 'com.google.protobuf:protobuf-java:2.5.+'
  }
  </code></pre>
  
  <p>When I run gradle build (version: 2.0) I get this failure</p>
  
  <pre><code>FAILURE: Build failed with an exception.
  
  * What went wrong:
  Could not resolve all dependencies for configuration ':datamodel:compile'.
  &gt; Could not find any version that matches com.google.protobuf:protobuf-java:2.5.+.
    Required by:
        MyRoot:datamodel:unspecified
  </code></pre>
  
  <p>How can I fix this?</p>