Print all permutations of string

Deadlock.java

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+
+
+/*Java program to demonstrate a solution for Deadlock in Multi-threading */
+
+public class Deadlock {
+
+	public static Object Resource1 = new Object(); /* Creating 2 objects in order to acquire lock */
+	public static Object Resource2 = new Object();
+
+	public static void main(String args[]) {
+
+		ThreadDemo1 T1 = new ThreadDemo1(); /* Creating 2 thread objects */
+		ThreadDemo2 T2 = new ThreadDemo2();
+
+		T1.start();
+		T2.start();
+	}
+
+	private static class ThreadDemo1 extends Thread { /* Illustration of thread by extending Thread class*/
+
+		public void run() {
+			synchronized (Resource1) {
+				System.out.println("Thread 1: Holding Resource 1..."); /* Thread 1 acquiring lock on Resource 1 */
+
+				try {
+					Thread.sleep(10);
+				} catch (InterruptedException e) {
+				}
+				System.out.println(
+						"Thread 1: Waiting for Resource 2..."); /*
+																 * Thread 1 in waiting state while it is trying to
+																 * acquire Resource 2 but already locked
+																 */
+
+				synchronized (Resource2) {
+					System.out
+							.println("Thread 1: Holding Resource 1 & 2..."); /* Thread 1 acquiring lock on Resource 2 */
+				}
+			}
+		}
+	}
+
+	private static class ThreadDemo2 extends Thread { /* Illustration of thread by extending Thread class*/
+		public void run() {
+			synchronized (Resource1) {
+				System.out.println("Thread 2: Holding Resource 1..."); /* Thread 2 acquiring lock on Resource 1 */
+
+				try {
+					Thread.sleep(10);
+				} catch (InterruptedException e) {
+				}
+				System.out.println(
+						"Thread 2: Waiting for Resource 2..."); /*
+																 * Thread 2 in waiting state while it is trying to
+																 * acquire Resource 2 but already locked
+																 */
+
+				synchronized (Resource2) {
+					System.out
+							.println("Thread 2: Holding Resource 1 & 2..."); /* Thread 2 acquiring lock on Resource 2 */
+				}
+			}
+		}
+	}
+}

Permutations.java

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+
+/* Java program to obtain permutations of a given string */
+
+public class Permutations {
+
+	/*
+	 * Function for swapping the characters at position i with character at position
+	 * j
+	 */
+
+	public static String swapString(String s, int i, int j) {
+
+		char[] b = s.toCharArray(); /* conversion of the string char array to perform swapping */
+
+		char ch;
+		ch = b[i];
+		b[i] = b[j];
+		b[j] = ch;
+		return String.valueOf(b);
+	}
+
+	/* Function for generating different permutations of the string */
+
+	public static void generatePermutation(String str, int start, int end) {
+
+		/* Prints the permutations */
+
+		if (start == end - 1)
+			System.out.println(str);
+		else {
+			for (int i = start; i < end; i++) {
+
+				/* Swapping the string by fixing a character */
+				str = swapString(str, start, i);
+
+				/*
+				 * Recursively calling function generatePermutation() for rest of the characters
+				 */
+				generatePermutation(str, start + 1, end);
+
+				/* Backtracking and swapping the characters again. */
+				str = swapString(str, start, i);
+			}
+		}
+	}
+
+	public static void main(String[] args) {
+
+		String str = "BAD";
+		int len = str.length(); /* Find the length of the given string */
+
+		System.out.println("All the permutations of the string are: ");
+		generatePermutation(str, 0, len);
+	}
+
+}