How to override method in uber jar?

Question

I am trying to use this code with Google Cloud Datastore:

Query<Entity> query = Query.entityQueryBuilder()
    .kind("Task")
    .filter(PropertyFilter.hasAncestor(
        datastore.newKeyFactory().kind("TaskList").newKey("default")))
    .build();
datastore.run(query, ReadOption.eventualConsistency());

I get this error:

Exception in thread "main" java.lang.VerifyError: class com.google.datastore.v1.ReadOptions$Builder overrides final method mergeUnknownFields.(Lcom/google/protobuf/UnknownFieldSet;)Lcom/google/protobuf/GeneratedMessage$Builder; at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClass(ClassLoader.java:763) at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142) at java.net.URLClassLoader.defineClass(URLClassLoader.java:467) at java.net.URLClassLoader.access$100(URLClassLoader.java:73) at java.net.URLClassLoader$1.run(URLClassLoader.java:368) at java.net.URLClassLoader$1.run(URLClassLoader.java:362) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:361) at java.lang.ClassLoader.loadClass(ClassLoader.java:424) at java.lang.ClassLoader.loadClass(ClassLoader.java:357) at com.google.datastore.v1.ReadOptions.toBuilder(ReadOptions.java:392) at com.google.datastore.v1.ReadOptions.newBuilder(ReadOptions.java:386) at com.google.cloud.datastore.DatastoreImpl.toReadOptionsPb(DatastoreImpl.java:217) at com.google.cloud.datastore.DatastoreImpl.run(DatastoreImpl.java:78)

Some general details:

• Language: scala
• Run on: Google compute engine
• Using com.google.guava:guava:19.0 and com.google.cloud:google-cloud:0.3.0 dependencies

• This is the code from google.datastore.v1.protos

  public final Builder mergeUnknownFields( final com.google.protobuf.UnknownFieldSet unknownFields) { return this; }

• this is the code from com.google.protobuf.GeneratedMessage

      public BuilderType mergeUnknownFields(UnknownFieldSet unknownFields) {
      this.unknownFields = UnknownFieldSet.newBuilder(this.unknownFields).mergeFrom(unknownFields).build();
      this.onChanged();
      return this;
  }
  

`

Answer 1

I believe this is a symptom of the issues described in this issue.

Answer 2

Adding Shaded Dependencies solved the spark/google cloud client api conflict problem by using:

<plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-shade-plugin</artifactId>
            <version>2.4.3</version>
            <executions>
                <execution>
                    <phase>package</phase>
                    <goals>
                        <goal>shade</goal>
                    </goals>
                    <configuration>
                        <relocations>
                            <relocation>
                                <pattern>com.google</pattern>
                                <shadedPattern>shaded.com.google</shadedPattern>
                            </relocation>
                        </relocations>
                    </configuration>
                </execution>
            </executions>
        </plugin>