Program: 25567
Project: 25567
Buggy source:
public BoxClient(final Parameters params){
  this.params=params;
  this.stack=params.stack;
  this.format=params.format;
  this.boxWidth=params.width;
  this.boxHeight=params.height;
  String boxName=this.boxWidth + "String_Node_Str" + this.boxHeight;
  if (params.label) {
    boxName+="String_Node_Str";
    this.backgroundRGBColor=Color.WHITE.getRGB();
  }
 else {
    this.backgroundRGBColor=null;
  }
  final Path boxPath=Paths.get(params.rootDirectory,params.project,params.stack,boxName).toAbsolutePath();
  this.boxDirectory=boxPath.toFile();
  final File stackDirectory=this.boxDirectory.getParentFile();
  if (!stackDirectory.exists()) {
    throw new IllegalArgumentException("String_Node_Str" + stackDirectory);
  }
  if (!stackDirectory.canWrite()) {
    throw new IllegalArgumentException("String_Node_Str" + stackDirectory);
  }
  this.emptyImageFile=new File(boxDirectory.getAbsolutePath(),"String_Node_Str" + format.toLowerCase());
  if (params.renderGroup != null) {
    if (params.numberOfRenderGroups == null) {
      throw new IllegalArgumentException("String_Node_Str");
    }
    if (params.renderGroup < 1) {
      throw new IllegalArgumentException("String_Node_Str");
    }
    if (params.renderGroup > params.numberOfRenderGroups) {
      throw new IllegalArgumentException("String_Node_Str" + params.numberOfRenderGroups + "String_Node_Str"+ params.renderGroup+ "String_Node_Str");
    }
  }
 else   if (params.numberOfRenderGroups != null) {
    throw new IllegalArgumentException("String_Node_Str");
  }
  this.renderDataClient=params.getClient();
}

Fixed version (ground truth):
public BoxClient(final Parameters params) throws IOException {
  this.params=params;
  this.stack=params.stack;
  this.format=params.format;
  this.boxWidth=params.width;
  this.boxHeight=params.height;
  String boxName=this.boxWidth + "String_Node_Str" + this.boxHeight;
  if (params.label) {
    boxName+="String_Node_Str";
    this.backgroundRGBColor=Color.WHITE.getRGB();
  }
 else {
    this.backgroundRGBColor=null;
  }
  final Path boxPath=Paths.get(params.rootDirectory,params.project,params.stack,boxName).toAbsolutePath();
  this.boxDirectory=boxPath.toFile();
  final File stackDirectory=this.boxDirectory.getParentFile();
  if (!stackDirectory.exists()) {
    throw new IllegalArgumentException("String_Node_Str" + stackDirectory);
  }
  if (!stackDirectory.canWrite()) {
    throw new IllegalArgumentException("String_Node_Str" + stackDirectory);
  }
  this.emptyImageFile=new File(boxDirectory.getAbsolutePath(),"String_Node_Str" + format.toLowerCase());
  if (params.renderGroup != null) {
    if (params.numberOfRenderGroups == null) {
      throw new IllegalArgumentException("String_Node_Str");
    }
    if (params.renderGroup < 1) {
      throw new IllegalArgumentException("String_Node_Str");
    }
    if (params.renderGroup > params.numberOfRenderGroups) {
      throw new IllegalArgumentException("String_Node_Str" + params.numberOfRenderGroups + "String_Node_Str"+ params.renderGroup+ "String_Node_Str");
    }
  }
 else   if (params.numberOfRenderGroups != null) {
    throw new IllegalArgumentException("String_Node_Str");
  }
  this.renderDataClient=params.getClient();
  final StackMetaData stackMetaData=this.renderDataClient.getStackMetaData(this.stack);
  this.stackBounds=stackMetaData.getStats().getStackBounds();
}