public boolean comparePasswords(String oldPassword, String newPassword) { int minLength = Math.min(oldPassword.length(), newPassword.length()); int matchingCharacters = 0; for (int i = 0; i < minLength; i++) { if (oldPassword.charAt(i) == newPassword.charAt(i)) { matchingCharacters++; } } // You can define a threshold for similarity double similarityThreshold = 0.8; double similarityRatio = (double) matchingCharacters / minLength; return similarityRatio >= similarityThreshold; }