I cant figure out why I keep getting an Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: Index 1 out of bounds for length 1 error on line 19

this is the full program for the above issue after whats shown in picture:

for (String compound : splitEquation) { if (j > 0) { balancedEquation.append("="); } List elements = splitCompound(compound); for (int k = 0; k parseSide(String side) { Map elements = new HashMap(); String[] compounds = side.split("\\+"); for (String compound : compounds) { compound = compound.trim(); int coeff = 1; int i = 0; if (Character.isDigit(compound.charAt(0))) { coeff = compound.charAt(0) - '0'; i++; } String element = ""; while (i splitCompound(String compound) { List elements = new ArrayList(); int i = 0; while (i subElements = splitCompound(subCompound); for (int k = 0; k balanceEquation(Map leftCounts, Map rightCounts) { List elements = new ArrayList(); for (String element : leftCounts.keySet()) { if (!elements.contains(element)) { elements.add(element); } } for (String element : rightCounts.keySet()) { if (!elements.contains(element)) { elements.add(element); } } int numElements = elements.size(); int numCompounds = 2; int[][] matrix = new int[numElements][numCompounds]; int[] rightSide = new int[numElements]; int i = 0; for (String element : elements) { if (leftCounts.containsKey(element)) { matrix[i][0] = leftCounts.get(element); } if (rightCounts.containsKey(element)) { matrix[i][1] = rightCounts.get(element); rightSide[i] = rightCounts.get(element); } i++; } int[] coefficients = solveEquation(matrix, rightSide); if (coefficients == null) { return null; } List coefficientList = new ArrayList(); for (int j = 0; j

public static int[] solveEquation(int[][] matrix, int[] rightSide) { int numRows = matrix.length; int numCols = matrix[0].length; for (int j = 0; j = 0; j--) { int sum = rightSide[j]; for (int k = j + 1; k

[ import java.util.* public class ChemicalEquationBalancer \&