Program: 2199
Project: 2199
Buggy source:
/** 
 * Process sampleCount sequential samples with identical values.  sampleCount will usually be 1, but may be larger than 1.  Implementors may just loop processing identical values, but some implementations may optimize adding a bunch of repeated values
 * @param timestamps   a TimelineTimestamps instance, indexed by sample number to get the time at which the sample was captured.
 * @param sampleNumber the number of the sample within the timeline, used to index timestamps
 * @param sampleCount  the count of sequential, identical values
 * @param opcode       the opcode of the sample value, which may not be a REPEAT opcode
 * @param value        the value of this kind of sample over the count of samples starting at the timegiven by the sampleNumber indexing the TimelineTimestamps.
 */
@Override public void processSamples(final TimelineTimes timestamps,final int sampleNumber,final int sampleCount,final SampleOpcode opcode,final Object value){
  for (int i=0; i < sampleCount; i++) {
    if (!firstSamples) {
      builder.append("String_Node_Str");
    }
 else {
      firstSamples=false;
    }
    final DateTime sampleTimestamp=timestamps.getSampleTimestamp(sampleNumber + i);
    if (sampleTimestamp == null) {
      continue;
    }
    builder.append(TimelineTimes.unixSeconds(sampleTimestamp)).append("String_Node_Str");
    if (opcode.getRepeater()) {
      builder.append(lastValue);
    }
 else {
      final String jsonValue=value == null ? "String_Node_Str" : value.toString();
      builder.append(jsonValue);
      lastValue=jsonValue;
    }
  }
}

Fixed version (ground truth):
/** 
 * Process sampleCount sequential samples with identical values.  sampleCount will usually be 1, but may be larger than 1.  Implementors may just loop processing identical values, but some implementations may optimize adding a bunch of repeated values
 * @param timestamps   a TimelineTimestamps instance, indexed by sample number to get the time at which the sample was captured.
 * @param sampleNumber the number of the sample within the timeline, used to index timestamps
 * @param sampleCount  the count of sequential, identical values
 * @param opcode       the opcode of the sample value, which may not be a REPEAT opcode
 * @param value        the value of this kind of sample over the count of samples starting at the timegiven by the sampleNumber indexing the TimelineTimestamps.
 */
@Override public void processSamples(final TimelineTimes timestamps,final int sampleNumber,final int sampleCount,final SampleOpcode opcode,final Object value){
  for (int i=0; i < sampleCount; i++) {
    final DateTime sampleTimestamp=timestamps.getSampleTimestamp(sampleNumber + i);
    if (sampleTimestamp == null) {
      continue;
    }
    if (!firstSamples) {
      builder.append("String_Node_Str");
    }
 else {
      firstSamples=false;
    }
    builder.append(TimelineTimes.unixSeconds(sampleTimestamp)).append("String_Node_Str");
    if (opcode.getRepeater()) {
      builder.append(lastValue);
    }
 else {
      final String jsonValue=value == null ? "String_Node_Str" : value.toString();
      builder.append(jsonValue);
      lastValue=jsonValue;
    }
  }
}