core/src/main/java/com/twitter/elephantbird/mapred/input/DeprecatedInputFormatWrapper.java
public static void setInputFormat(Class<?> realInputFormatClass, JobConf jobConf) {
    jobConf.setInputFormat(DeprecatedInputFormatWrapper.class);
    HadoopUtils.setClassConf(jobConf, CLASS_CONF_KEY, realInputFormatClass);
  }
public static void setInputFormat(Class<?> realInputFormatClass, JobConf jobConf) {
    jobConf.setInputFormat(DeprecatedInputFormatWrapper.class);
    HadoopUtils.setClassConf(jobConf, CLASS_CONF_KEY, realInputFormatClass);
  }
Sets jobs input format to {@link DeprecatedInputFormatWrapper} and stores
supplied real {@link InputFormat} class name in job configuration.
This configuration is read on the remote tasks to instantiate actual
InputFormat correctly.