title: Cannot resolve symbol class while implementing server from proto buff - unary API
body: <p><strong>Gradle project</strong> </p>
  
  <p>Tying to implement grpc - unary API using java-gradle project</p>
  
  <p><strong>Build.gradle</strong></p>
  
  <blockquote>
    <p>group = "com.kaushik.grpc"
        version = "1.0-SNAPSHOT"</p>
  
  <pre><code>apply plugin: 'java'
  apply plugin: 'com.google.protobuf'
  apply plugin: 'idea'
  
  buildscript {
      repositories {
          mavenCentral()
      }
      dependencies {
          classpath 'com.google.protobuf:protobuf-gradle-plugin:0.8.5'
      }
  }
  
  repositories {
      mavenCentral()
  }
  
  description = "gRPC Java Examples"
  
  dependencies {
      compile 'io.grpc:grpc-all:0.13.1'
  }
  
  
  protobuf {
      protoc {
          // The version of protoc must match protobuf-java. If you don't depend on
          // protobuf-java directly, you will be transitively depending on the
          // protobuf-java version that grpc depends on.
          artifact = "com.google.protobuf:protoc:3.0.0-beta-2"
      }
      plugins {
          grpc {
              artifact = 'io.grpc:protoc-gen-grpc-java:0.13.1'
          }
      }
      generateProtoTasks {
          all()*.plugins {
              grpc {}
          }
      }
  }
  </code></pre>
  </blockquote>
  
  <p><strong>greet.proto</strong></p>
  
  <blockquote>
  <pre><code>syntax = "proto3";
  
  package greet;
  
  option java_package = "com.proto.greet";
  option java_multiple_files = true;
  
  message Greeting {
      string first_name = 1;
      string last_name = 2;
  }
  
  message GreetRequest {
      Greeting greeting = 1;
  }
  
  message GreetResponse {
      string result = 1;
  }
  
  service GreetService {
      //unary
      rpc Greet(GreetRequest) returns (GreetResponse) {};
  }
  </code></pre>
  </blockquote>
  
  <p><strong>while trying to extend GreetServiceGrpc</strong></p>
  
  <blockquote>
  <pre><code>import com.proto.greet.GreetServiceGrpc;
  public class GreetServiceImpl extends GreetServiceGrpc.GreetServiceImplBase{
  
  }
  </code></pre>
  </blockquote>
  
  <p>Cannot resolve symbol GreetServiceImplBase.
  There is no class with GreetServiceImplBase even in build path.</p>