basic-lib/src/main/java/com/streamsets/pipeline/lib/http/HttpClientCommon.java
public MultivaluedMap<String, Object> resolveHeaders(
      Map<String, String> headers,
      Record record
  ) throws StageException {
    RecordEL.setRecordInContext(headerVars, record);

    MultivaluedMap<String, Object> requestHeaders = new MultivaluedHashMap<>();
    for (Map.Entry<String, String> entry : headers.entrySet()) {
      List<Object> header = new ArrayList<>(1);
      Object resolvedValue = headerEval.eval(headerVars, entry.getValue(), String.class);
      header.add(resolvedValue);
      requestHeaders.put(entry.getKey(), header);
    }

    return requestHeaders;
  }
public MultivaluedMap<String, Object> resolveHeaders(
      Map<String, String> headers,
      Record record
  ) throws StageException {
    RecordEL.setRecordInContext(headerVars, record);

    MultivaluedMap<String, Object> requestHeaders = new MultivaluedHashMap<>();
    for (Map.Entry<String, String> entry : headers.entrySet()) {
      List<Object> header = new ArrayList<>(1);
      Object resolvedValue = headerEval.eval(headerVars, entry.getValue(), String.class);
      header.add(resolvedValue);
      requestHeaders.put(entry.getKey(), header);
    }

    return requestHeaders;
  }
Evaluates any EL expressions in the headers section of the stage configuration.

@param record current record in context for EL evaluation
@return Map of headers that can be added to the Jersey Client request
@throws StageException if an expression could not be evaluated