09. స్ట్రింగ్స్ డీప్ డైవ్ — String Constant Pool (SCP) & ఇమ్మ్యుటబిలిటీ (Strings & SCP)

public class StringPoolMemoryProof {
    public static void main(String[] args) {
        System.out.println("==================================================");
        System.out.println("     STRING CONSTANT POOL (SCP) MEMORY AUDIT      ");
        System.out.println("==================================================");

        // String Literals - Stored in SCP
        String literal1 = "Hyderabad";
        String literal2 = "Hyderabad";

        // Created using 'new' operator - Stored in standard Heap
        String heapString1 = new String("Hyderabad");
        String heapString2 = new String("Hyderabad");

        // Identity comparison via == (Memory Address)
        System.out.println("[SCP Literal == Literal]  : " + (literal1 == literal2) + " (Same SCP Object)");
        System.out.println("[SCP Literal == Heap Obj] : " + (literal1 == heapString1) + " (Different Locations!)");
        System.out.println("[Heap Obj == Heap Obj]    : " + (heapString1 == heapString2) + " (Two Distinct Objects)");

        // Content comparison via .equals()
        System.out.println("--------------------------------------------------");
        System.out.println("[literal1.equals(heapString1)] : " + literal1.equals(heapString1) + " (Content Matched)");

        // Invoking intern() to retrieve SCP pooled reference
        String internedString = heapString1.intern();
        System.out.println("[literal1 == heapString1.intern()] : " + (literal1 == internedString) + " (Pooled via intern!)");
        System.out.println("==================================================");
    }
}

public class PalindromeStringAnalyzer {
    public static void main(String[] args) {
        String testWord = "Madam";
        String normalized = testWord.trim().toLowerCase();

        int left = 0;
        int right = normalized.length() - 1;
        boolean isPalindrome = true;

        while (left < right) {
            if (normalized.charAt(left) != normalized.charAt(right)) {
                isPalindrome = false;
                break;
            }
            left++;
            right--;
        }

        System.out.println("--------------------------------------------------");
        System.out.println("         STRING PALINDROME VERIFIER ENGINE        ");
        System.out.println("--------------------------------------------------");
        System.out.println("Input String   : " + testWord);
        System.out.println("Normalized Text: " + normalized);
        System.out.println("Word Length    : " + testWord.length());
        System.out.println("Is Palindrome? : " + (isPalindrome ? "YES (100% Symmetrical)" : "NO"));
        System.out.println("--------------------------------------------------");
    }
}

public class SecurityCredentialValidatorEngine {
    public static void main(String[] args) {
        String username = "kiran_kumar";
        String password = "P@ssw0rd2026#Enterprise";

        System.out.println("==================================================");
        System.out.println("       IDENTITY & PASSWORD STRENGTH VALIDATOR      ");
        System.out.println("==================================================");

        boolean hasUpper = false;
        boolean hasLower = false;
        boolean hasDigit = false;
        boolean hasSpecial = false;
        String specialChars = "!@#$%^&*()-_+=<>?";

        for (int i = 0; i < password.length(); i++) {
            char ch = password.charAt(i);
            if (Character.isUpperCase(ch)) hasUpper = true;
            else if (Character.isLowerCase(ch)) hasLower = true;
            else if (Character.isDigit(ch)) hasDigit = true;
            else if (specialChars.contains(String.valueOf(ch))) hasSpecial = true;
        }

        int strengthScore = 0;
        if (password.length() >= 12) strengthScore += 25;
        if (hasUpper) strengthScore += 25;
        if (hasLower && hasDigit) strengthScore += 25;
        if (hasSpecial) strengthScore += 25;

        String strengthRating = switch (strengthScore) {
            case 100 -> "VERY STRONG (Military Grade Encryption Ready)";
            case 75  -> "STRONG (Exceeds Standard Enterprise Cutoff)";
            case 50  -> "MODERATE (Vulnerable to Dictionary Attacks)";
            default  -> "WEAK (Immediate Reset Mandated)";
        };

        System.out.println("Account User : " + username);
        System.out.println("Password Len : " + password.length() + " chars");
        System.out.printf("Upper: %b | Lower: %b | Digit: %b | Special: %b%n", 
                          hasUpper, hasLower, hasDigit, hasSpecial);
        System.out.println("--------------------------------------------------");
        System.out.printf("Strength Score: %d / 100%n", strengthScore);
        System.out.println("Security Audit: " + strengthRating);
        System.out.println("==================================================");
    }
}