Program: 164205
Project: 164205
Buggy source:
private static void layoutButtons(ArrayList<RedButton> line,float extraWidth,float y){
  if (line == null || line.size() == 0 || extraWidth == 0)   return;
  if (line.size() == 1) {
    line.get(0).setSize(line.get(0).width() + extraWidth,BUTTON_HEIGHT);
    return;
  }
  ArrayList<RedButton> lineByWidths=new ArrayList<>(line);
  Collections.sort(lineByWidths,widthComparator);
  RedButton smallest, middle, largest;
  smallest=lineByWidths.get(0);
  middle=lineByWidths.get(1);
  largest=null;
  if (lineByWidths.size() == 3) {
    largest=lineByWidths.get(2);
  }
  float btnDiff=middle.width() - smallest.width();
  smallest.setSize(smallest.width() + Math.min(btnDiff,extraWidth),BUTTON_HEIGHT);
  extraWidth-=btnDiff;
  if (extraWidth > 0) {
    if (largest == null) {
      smallest.setSize(smallest.width() + extraWidth / 2,BUTTON_HEIGHT);
      middle.setSize(middle.width() + extraWidth / 2,BUTTON_HEIGHT);
    }
 else {
      btnDiff=largest.width() - smallest.width();
      smallest.setSize(smallest.width() + Math.min(btnDiff,extraWidth / 2),BUTTON_HEIGHT);
      middle.setSize(middle.width() + Math.min(btnDiff,extraWidth / 2),BUTTON_HEIGHT);
      extraWidth-=btnDiff * 2;
      if (extraWidth > 0) {
        smallest.setSize(smallest.width() + extraWidth / 3,BUTTON_HEIGHT);
        middle.setSize(middle.width() + extraWidth / 3,BUTTON_HEIGHT);
        largest.setSize(largest.width() + extraWidth / 3,BUTTON_HEIGHT);
      }
    }
  }
  float x=0;
  for (  RedButton btn : line) {
    btn.setPos(x,y);
    x+=btn.width() + 1;
  }
}

Fixed version (ground truth):
private static void layoutButtons(ArrayList<RedButton> line,float extraWidth,float y){
  if (line == null || line.size() == 0 || extraWidth == 0)   return;
  if (line.size() == 1) {
    line.get(0).setSize(line.get(0).width() + extraWidth,BUTTON_HEIGHT);
    line.get(0).setPos(0,y);
    return;
  }
  ArrayList<RedButton> lineByWidths=new ArrayList<>(line);
  Collections.sort(lineByWidths,widthComparator);
  RedButton smallest, middle, largest;
  smallest=lineByWidths.get(0);
  middle=lineByWidths.get(1);
  largest=null;
  if (lineByWidths.size() == 3) {
    largest=lineByWidths.get(2);
  }
  float btnDiff=middle.width() - smallest.width();
  smallest.setSize(smallest.width() + Math.min(btnDiff,extraWidth),BUTTON_HEIGHT);
  extraWidth-=btnDiff;
  if (extraWidth > 0) {
    if (largest == null) {
      smallest.setSize(smallest.width() + extraWidth / 2,BUTTON_HEIGHT);
      middle.setSize(middle.width() + extraWidth / 2,BUTTON_HEIGHT);
    }
 else {
      btnDiff=largest.width() - smallest.width();
      smallest.setSize(smallest.width() + Math.min(btnDiff,extraWidth / 2),BUTTON_HEIGHT);
      middle.setSize(middle.width() + Math.min(btnDiff,extraWidth / 2),BUTTON_HEIGHT);
      extraWidth-=btnDiff * 2;
      if (extraWidth > 0) {
        smallest.setSize(smallest.width() + extraWidth / 3,BUTTON_HEIGHT);
        middle.setSize(middle.width() + extraWidth / 3,BUTTON_HEIGHT);
        largest.setSize(largest.width() + extraWidth / 3,BUTTON_HEIGHT);
      }
    }
  }
  float x=0;
  for (  RedButton btn : line) {
    btn.setPos(x,y);
    x+=btn.width() + 1;
  }
}