core/src/main/java/com/twitter/elephantbird/mapred/input/DeprecatedInputFormatWrapper.java
public static void setInputFormat(Class<?> realInputFormatClass, Configuration conf) {
    conf.setClass("mapred.input.format.class", DeprecatedInputFormatWrapper.class, org.apache.hadoop.mapred.InputFormat.class);
    HadoopUtils.setClassConf(conf, CLASS_CONF_KEY, realInputFormatClass);
  }
public static void setInputFormat(Class<?> realInputFormatClass, Configuration conf) {
    conf.setClass("mapred.input.format.class", DeprecatedInputFormatWrapper.class, org.apache.hadoop.mapred.InputFormat.class);
    HadoopUtils.setClassConf(conf, CLASS_CONF_KEY, realInputFormatClass);
  }
For cases where we need to set hadoop1 input format in a hadoop2 Configuration object.