Question

I have a myprotofile.proto file that looks like this

 package PBPackage;
 message SomeMessage {
    required double someItem = 1;
 }

I build it like this (I’m on linux)

 JAVADIR=../../MyJarFile.jar
 protoc -I=. --java_out=${JAVADIR} myprotofile.proto

My Java program, Program.java, looks like this

 import PBPackage.SomeMessage;
 public class Program {
      public static void main( String[] args ){
           System.out.println( "this is my program" );
      }
  }

I try to build Program.java like this

 javac -cp .:MyJarFile.jar Program.java

But I always get this error:

 Program.java:1 error cannot find symbol
 import PBPackage.SomeMessage;
                 ^
 symbol:           class SomeMessage
 location:         package PBPackage

What am I doing wrong?

Finally, please don’t tell me to use some overly complicated build system like ant or maven.

Answer 1

Most probably your JAR file contains this class in different package than you expect it.

There are two options you can use in your protobuf definition file to explicitly specify package and class name for generated code:

option java_package = "com.example.tutorial";
option java_outer_classname = "AddressBookProtos";

Please check this tutorial for more information.