Program: 109858
Project: 109858
Buggy source:
@Override public boolean generate(BlockPos pos){
  int i=pos.getX();
  int j=pos.getY();
  int k=pos.getZ();
  Block blockUnder=getBlock(i,j - 1,k);
  if (blockUnder != Blocks.SAND) {
    return false;
  }
  int height=9 + rand.nextInt(3);
  int dir=this.pickDirection(i,j,k);
  this.setDir(dir);
  this.setOrigin(i,k);
  for (int x=0; x < 4; x++) {
    for (int y=0; y < height; y++) {
      if (this.getBlockWithDir(x,y + j,0) != Blocks.AIR) {
        return false;
      }
    }
  }
  for (int x=0; x < 9; x++) {
    for (int z=0; z < 9; z++) {
      for (int y=height - 3; y < height + 4; y++) {
        if (this.getBlockWithDir(x + TOP_OFFSET,y + j,z) != Blocks.AIR) {
          return false;
        }
      }
    }
  }
  for (int x=0, y=0; y < height; y++) {
    this.placeBlockWithDir(x,y + j,0,woodState);
    if (y == 0 || y == 1 || y == 3) {
      x++;
      this.placeBlockWithDir(x,y + j,0,woodState);
    }
  }
  this.setOrigin(this.getActualXAt(TOP_OFFSET,0),this.getActualZAt(TOP_OFFSET,0));
  for (int y=1; y < 5; y++) {
    if (y == 4) {
      this.placeBlockWithDir(1,y + j + height - 1,0,leafState);
    }
 else {
      this.placeBlockWithDir(0,y + j + height - 1,0,leafState);
    }
  }
  for (int curDir=0; curDir < 4; curDir++) {
    this.setDir(curDir);
    int y=height - 1;
    this.placeBlockWithDir(1,y - 1 + j,1,leafState);
    this.placeBlockWithDir(2,y - 2 + j,1,leafState);
    this.placeBlockWithDir(1,y - 2 + j,2,leafState);
    this.placeBlockWithDir(2,y - 3 + j,2,leafState);
    this.placeBlockWithDir(1,y + 1 + j,1,leafState);
    this.placeBlockWithDir(2,y + 2 + j,1,leafState);
    this.placeBlockWithDir(1,y + 2 + j,2,leafState);
    this.placeBlockWithDir(2,y + 3 + j,2,leafState);
    System.out.println("String_Node_Str" + this.getActualXAt(1,1) + "String_Node_Str"+ this.getActualZAt(1,1)+ "String_Node_Str"+ curDir);
    for (int x=1; x < 5; x++) {
      if (x == 4) {
        y--;
      }
      this.placeBlockWithDir(x,y + j,0,leafState);
    }
  }
  return true;
}

Fixed version (ground truth):
@Override public boolean generate(BlockPos pos){
  int i=pos.getX();
  int j=pos.getY();
  int k=pos.getZ();
  Block blockUnder=getBlock(i,j - 1,k);
  if (blockUnder != Blocks.SAND) {
    return false;
  }
  int height=9 + rand.nextInt(3);
  int dir=this.pickDirection(i,j,k);
  this.setDir(dir);
  this.setOrigin(i,k);
  for (int x=0; x < 4; x++) {
    for (int y=0; y < height; y++) {
      if (this.getBlockWithDir(x,y + j,0) != Blocks.AIR) {
        return false;
      }
    }
  }
  for (int x=0; x < 9; x++) {
    for (int z=0; z < 9; z++) {
      for (int y=height - 3; y < height + 4; y++) {
        if (this.getBlockWithDir(x + TOP_OFFSET,y + j,z) != Blocks.AIR) {
          return false;
        }
      }
    }
  }
  for (int x=0, y=0; y < height; y++) {
    this.placeBlockWithDir(x,y + j,0,woodState);
    if (y == 0 || y == 1 || y == 3) {
      x++;
      this.placeBlockWithDir(x,y + j,0,woodState);
    }
  }
  this.setOrigin(this.getActualXAt(TOP_OFFSET,0),this.getActualZAt(TOP_OFFSET,0));
  for (int y=1; y < 5; y++) {
    if (y == 4) {
      this.placeBlockWithDir(1,y + j + height - 1,0,leafState);
    }
 else {
      this.placeBlockWithDir(0,y + j + height - 1,0,leafState);
    }
  }
  for (int curDir=0; curDir < 4; curDir++) {
    this.setDir(curDir);
    int y=height - 1;
    this.placeBlockWithDir(1,y - 1 + j,1,leafState);
    this.placeBlockWithDir(2,y - 2 + j,1,leafState);
    this.placeBlockWithDir(1,y - 2 + j,2,leafState);
    this.placeBlockWithDir(2,y - 3 + j,2,leafState);
    this.placeBlockWithDir(1,y + 1 + j,1,leafState);
    this.placeBlockWithDir(2,y + 2 + j,1,leafState);
    this.placeBlockWithDir(1,y + 2 + j,2,leafState);
    this.placeBlockWithDir(2,y + 3 + j,2,leafState);
    for (int x=1; x < 5; x++) {
      if (x == 4) {
        y--;
      }
      this.placeBlockWithDir(x,y + j,0,leafState);
    }
  }
  return true;
}