Program: 61537
Project: 61537
Buggy source:
public String getSolutionData(List<ProgramVariant> variants,int generation){
  String line="String_Node_Str";
  line+="String_Node_Str";
  for (  ProgramVariant solutionVariant : variants) {
    line+="String_Node_Str";
    line+="String_Node_Str" + solutionVariant.getId() + "String_Node_Str";
    line+="String_Node_Str" + TimeUtil.getDateDiff(this.dateInitEvolution,solutionVariant.getBornDate(),TimeUnit.SECONDS);
    for (int i=1; i <= generation; i++) {
      List<OperatorInstance> genOperationInstances=solutionVariant.getOperations().get(i);
      if (genOperationInstances == null)       continue;
      for (      OperatorInstance genOperationInstance : genOperationInstances) {
        line+="String_Node_Str" + genOperationInstance.getOperationApplied().toString() + "String_Node_Str"+ genOperationInstance.getModificationPoint().getCtClass().getQualifiedName();
        if (genOperationInstance.getModificationPoint() instanceof SuspiciousModificationPoint) {
          SuspiciousModificationPoint gs=(SuspiciousModificationPoint)genOperationInstance.getModificationPoint();
          line+="String_Node_Str" + gs.getSuspicious().getLineNumber();
          line+="String_Node_Str" + gs.getSuspicious().getSuspiciousValueString();
        }
        line+="String_Node_Str" + genOperationInstance.getOriginal().toString();
        line+="String_Node_Str";
        if (genOperationInstance.getModified() != null)         line+=genOperationInstance.getModified().toString();
 else {
          line+=genOperationInstance.getOriginal().toString();
        }
        line+="String_Node_Str" + Integer.toString(i);
        line+="String_Node_Str" + ((genOperationInstance.getIngredientScope() != null) ? genOperationInstance.getIngredientScope() : "String_Node_Str");
      }
    }
    line+="String_Node_Str" + solutionVariant.getValidationResult().toString();
  }
  return line;
}

Fixed version (ground truth):
public String getSolutionData(List<ProgramVariant> variants,int generation){
  String line="String_Node_Str";
  line+="String_Node_Str";
  for (  ProgramVariant solutionVariant : variants) {
    line+="String_Node_Str";
    line+="String_Node_Str" + solutionVariant.getId() + "String_Node_Str";
    line+="String_Node_Str" + TimeUtil.getDateDiff(this.dateInitEvolution,solutionVariant.getBornDate(),TimeUnit.SECONDS);
    for (int i=1; i <= generation; i++) {
      List<OperatorInstance> genOperationInstances=solutionVariant.getOperations().get(i);
      if (genOperationInstances == null)       continue;
      for (      OperatorInstance genOperationInstance : genOperationInstances) {
        line+="String_Node_Str" + genOperationInstance.getOperationApplied().toString() + "String_Node_Str"+ genOperationInstance.getModificationPoint().getCtClass().getQualifiedName();
        if (genOperationInstance.getModificationPoint() instanceof SuspiciousModificationPoint) {
          SuspiciousModificationPoint gs=(SuspiciousModificationPoint)genOperationInstance.getModificationPoint();
          line+="String_Node_Str" + gs.getSuspicious().getLineNumber();
          line+="String_Node_Str" + gs.getSuspicious().getSuspiciousValueString();
        }
        line+="String_Node_Str" + genOperationInstance.getOriginal().toString();
        line+="String_Node_Str";
        if (genOperationInstance.getModified() != null)         if (genOperationInstance.getModified().toString() != genOperationInstance.getOriginal().toString())         line+=genOperationInstance.getModified().toString();
 else {
          line+=genOperationInstance.getOriginal().toString();
        }
        line+="String_Node_Str" + Integer.toString(i);
        line+="String_Node_Str" + ((genOperationInstance.getIngredientScope() != null) ? genOperationInstance.getIngredientScope() : "String_Node_Str");
      }
    }
    line+="String_Node_Str" + solutionVariant.getValidationResult().toString();
  }
  return line;
}