Initial data commit

Task/Password-generator/Java/password-generator.java

@@ -0,0 +1,66 @@
+import java.util.*;
+
+public class PasswordGenerator {
+    final static Random rand = new Random();
+
+    public static void main(String[] args) {
+        int num, len;
+
+        try {
+            if (args.length != 2)
+                throw new IllegalArgumentException();
+
+            len = Integer.parseInt(args[0]);
+            if (len < 4 || len > 16)
+                throw new IllegalArgumentException();
+
+            num = Integer.parseInt(args[1]);
+            if (num < 1 || num > 10)
+                throw new IllegalArgumentException();
+
+            for (String pw : generatePasswords(num, len))
+                System.out.println(pw);
+
+        } catch (IllegalArgumentException e) {
+            String s = "Provide the length of the passwords (min 4, max 16) you "
+                    + "want to generate,\nand how many (min 1, max 10)";
+            System.out.println(s);
+        }
+    }
+
+    private static List<String> generatePasswords(int num, int len) {
+        final String s = "!\"#$%&'()*+,-./:;<=>?@[]^_{|}~";
+
+        List<String> result = new ArrayList<>();
+
+        for (int i = 0; i < num; i++) {
+            StringBuilder sb = new StringBuilder();
+            sb.append(s.charAt(rand.nextInt(s.length())));
+            sb.append((char) (rand.nextInt(10) + '0'));
+            sb.append((char) (rand.nextInt(26) + 'a'));
+            sb.append((char) (rand.nextInt(26) + 'A'));
+
+            for (int j = 4; j < len; j++) {
+                int r = rand.nextInt(93) + '!';
+                if (r == 92 || r == 96) {
+                    j--;
+                } else {
+                    sb.append((char) r);
+                }
+            }
+            result.add(shuffle(sb));
+        }
+        return result;
+    }
+
+    public static String shuffle(StringBuilder sb) {
+        int len = sb.length();
+        for (int i = len - 1; i > 0; i--) {
+            int r = rand.nextInt(i);
+            char tmp = sb.charAt(i);
+            sb.setCharAt(i, sb.charAt(r));
+            sb.setCharAt(r, tmp);
+        }
+        return sb.toString();
+    }
+}