value-processor/src/org/immutables/value/processor/meta/Constitution.java
private String inPackage(String topLevel, String... nested) {
    return DOT_JOINER.join(null, topLevel, (Object[]) nested);
  }
private String inPackage(String topLevel, String... nested) {
    return DOT_JOINER.join(null, topLevel, (Object[]) nested);
  }
Package relative path
@param topLevel
@param nested
@return