mapreduce-protolib/src/main/java/com/streamsets/pipeline/stage/destination/mapreduce/jobtype/avroconvert/AvroConversionBaseMapper.java
protected boolean propertyDefined(Configuration conf, String propertyName) {
    String prop = conf.get(propertyName);
    // String property will have default empty, integer -1, we'll skip both of them
    return prop != null && !prop.isEmpty() && !prop.equals("-1");
  }
protected boolean propertyDefined(Configuration conf, String propertyName) {
    String prop = conf.get(propertyName);
    // String property will have default empty, integer -1, we'll skip both of them
    return prop != null && !prop.isEmpty() && !prop.equals("-1");
  }
Return true if and only if given property is defined with non empty non default value