Program: 181100
Project: 181100
Buggy source:
@Override public boolean isValid(){
  Square temp;
  Square temp2;
  boolean valid=true;
  int destination_col=destination.getCol();
  int destination_row=destination.getRow();
  int start_col=start.getCol();
  int start_row=start.getRow();
  Square between=isTwoAway(start,destination);
  if (destination_col > 8 || destination_col < 0 || destination_row > 8 || destination_row < 0) {
    valid=false;
  }
 else   if (start == destination) {
    valid=false;
  }
 else   if (isAdjacent(start,destination)) {
    if (setting.wallBetween(start,destination) || destination.hasPawn()) {
      valid=false;
    }
  }
 else   if (between != null) {
    if (!between.hasPawn()) {
      valid=false;
    }
 else     if (setting.wallBetween(start,between) || setting.wallBetween(between,destination)) {
      valid=false;
    }
  }
 else   if (destination_col - start_col == 1 && destination_row - start_row == 1) {
    temp=new SquareImpl(destination_col,destination_row - start_row);
    temp2=new SquareImpl(destination_col - start_col,destination_col);
    if (!temp.hasPawn() && !temp2.hasPawn()) {
      valid=false;
    }
  }
 else   if (destination_col + start_col == 1 && destination_row - start_row == 1) {
    temp=new SquareImpl(destination_col,destination_row - start_row);
    temp2=new SquareImpl(destination_col + start_col,destination_col);
    if (!temp.hasPawn() && !temp2.hasPawn()) {
      valid=false;
    }
  }
 else   if (destination_col - start_col == 1 && destination_row + start_row == 1) {
    temp=new SquareImpl(destination_col,destination_row + start_row);
    temp2=new SquareImpl(destination_col - start_col,destination_col);
    if (!temp.hasPawn() && !temp2.hasPawn()) {
      valid=false;
    }
  }
 else   if (destination_col + start_col == 1 && destination_row + start_row == 1) {
    temp=new SquareImpl(destination_col,destination_row + start_row);
    temp2=new SquareImpl(destination_col + start_col,destination_col);
    if (!temp.hasPawn() && !temp2.hasPawn()) {
      valid=false;
    }
  }
  return valid;
}

Fixed version (ground truth):
@Override public boolean isValid(){
  Square temp;
  Square temp2;
  boolean valid=true;
  int destination_col=destination.getCol();
  int destination_row=destination.getRow();
  int start_col=start.getCol();
  int start_row=start.getRow();
  Square between=isTwoAway(start,destination);
  if (destination_col > 8 || destination_col < 0 || destination_row > 8 || destination_row < 0) {
    valid=false;
  }
 else   if (start == destination) {
    valid=false;
  }
 else   if (isAdjacent(start,destination)) {
    if (setting.wallBetween(start,destination) || destination.hasPawn()) {
      valid=false;
    }
  }
 else   if (between != null) {
    if (!between.hasPawn()) {
      valid=false;
    }
 else     if (setting.wallBetween(start,between) || setting.wallBetween(between,destination)) {
      valid=false;
    }
  }
 else   if (destination_col - start_col == 1 && destination_row - start_row == 1) {
    temp=new SquareImpl(destination_col,destination_row - start_row);
    temp2=new SquareImpl(destination_col - start_col,destination_col);
    if (!temp.hasPawn() && !temp2.hasPawn()) {
      valid=false;
    }
  }
 else   if (destination_col + start_col == 1 && destination_row - start_row == 1) {
    temp=new SquareImpl(destination_col,destination_row - start_row);
    temp2=new SquareImpl(destination_col + start_col,destination_col);
    if (!temp.hasPawn() && !temp2.hasPawn()) {
      valid=false;
    }
  }
 else   if (destination_col - start_col == 1 && destination_row + start_row == 1) {
    temp=new SquareImpl(destination_col,destination_row + start_row);
    temp2=new SquareImpl(destination_col - start_col,destination_col);
    if (!temp.hasPawn() && !temp2.hasPawn()) {
      valid=false;
    }
  }
 else   if (destination_col + start_col == 1 && destination_row + start_row == 1) {
    temp=new SquareImpl(destination_col,destination_row + start_row);
    temp2=new SquareImpl(destination_col + start_col,destination_col);
    if (!temp.hasPawn() && !temp2.hasPawn()) {
      valid=false;
    }
  }
 else {
    valid=false;
  }
  return valid;
}