A java practice problem

Your logic is incorrect. This should do it:

public boolean makeBricks(int small, int big, int goal) {
  if (goal < 0 || big < 0 || small < 0) {
    throw new IllegalArgumentException();
  } else if (goal > big * 5 + small) {
    return false;
  } else if (goal % 5 <= small) {
    return true;
  } else {
    return false;
  }
}

is sufficient. This can be simplified to:

public boolean makeBricks(int small, int big, int goal) {
  if (goal < 0 || big < 0 || small < 0) {
    throw new IllegalArgumentException();
  } else {
    return goal <= big * 5 + small && goal % 5 <= small;
  }
}

Of course, the sanity check on negative goal, small or big is not strictly required but recommended. Without those checks, the result can simply be obtained by:

public boolean makeBricks(int small, int big, int goal) {
  return goal <= big * 5 + small && goal % 5 <= small;
}

I think you can just remove your second test. I would try this:

public boolean makeBricks(int small, int big, int goal) {
    if (goal > small + big * 5)
        return false;
    else
        return goal % 5 <= small;
}

The first test just checks how long the row would be if we just put all the bricks in a row. If that's not as long as the goal, then we know that it's impossible.

Next, we calculate the minimum number of small bricks: goal % 5. For example, if the goal is 8 and we have 1000 large bricks, how many small bricks do we need? 8 % 5 is 3, so we need 3 small bricks at the end of the row.

If we have enough small bricks, and the total length of all the bricks is enough, then we can meet the goal.