public Builder setCompanies(int index, java.lang.String value) {
      if (value == null) {
        throw new NullPointerException();
      }
      ensureCompaniesIsMutable();
      companies_.set(index, value);
      bitField0_ |= 0x00000004;
      onChanged();
      return this;
    }
<pre>
This filter specifies the company entities to search against.

If a value isn't specified, jobs are searched for against all
companies.

If multiple values are specified, jobs are searched against the
companies specified.

The format is
"projects/{project_id}/tenants/{tenant_id}/companies/{company_id}". For
example, "projects/foo/tenants/bar/companies/baz".

At most 20 company filters are allowed.
</pre>

<code>repeated string companies = 2;</code>

@param index The index to set the value at.
@param value The companies to set.
@return This builder for chaining.
java-talent/proto-google-cloud-talent-v4/src/main/java/com/google/cloud/talent/v4/JobQuery.java