Add ThreadPool

src/main/java/Main.java

@@ -5,7 +5,38 @@ import java.io.IOException;
 
 public class Main {
     public static void main(String[] args) throws IOException {
-//        JavaPipe.PipeMain();
-        TransferSpam.main();
+        JavaPipe.PipeMain();
+        //TransferSpam.main();
+    }
+}
+
+class RecursiveMath{
+    public static int add(int a, int b){
+        if(b < 1){
+            return a;
+        }
+        return add(a+1, b-1);
+    }
+
+    public static int multiply(int a, int b) {
+        if (b < 0) {
+            return -multiply(a, -b);
+        } else if (b == 0) {
+            return 0;
+        } else {
+            return add(a, multiply(a, b - 1));
+        }
+    }
+
+    public static int expo(int a, int b){
+        if (b==0){
+            return 1;
+        }else if (b == 1) {
+            return a;
+        }
+        return multiply(a, expo(a, b-1));
+    }
+    public static void main(String[] args) {
+        System.out.println(expo(2,6));
     }
 }

src/main/java/Threadpool/ThreadPool.java

@@ -0,0 +1,42 @@
+package Threadpool;
+
+import java.util.Vector;
+import java.util.concurrent.*;
+import static java.util.concurrent.Executors.newFixedThreadPool;
+
+public class ThreadPool {
+    private class Calculation implements Callable{
+        @Override
+        public Object call() throws Exception {
+            Thread.sleep(1000);
+            return 42;
+        }
+    }
+    public int doCalculation() throws ExecutionException, InterruptedException {
+        int totalResult = 0;
+        int threadPoolSize = 5;
+        int numberOfCalculations = 10;
+
+        Vector<Future<Integer>> allResults = new Vector<>();
+        ExecutorService threadpool = newFixedThreadPool(threadPoolSize);
+
+        for (int i = 0; i < numberOfCalculations; i++) {
+            Future<Integer> oneResult = threadpool.submit(new Calculation());
+            allResults.add(oneResult);
+        }
+
+        for (Future<Integer> result : allResults) {
+            totalResult += result.get();
+        }
+
+        threadpool.shutdown();
+        return totalResult;
+    }
+
+    public static void main(String[] args) throws ExecutionException, InterruptedException {
+        ThreadPool test = new ThreadPool();
+        System.out.println("Calculation started");
+        int result = test.doCalculation();
+        System.out.println("Result: " + result);
+    }
+}

src/main/java/smartBank/TransferSpam.java

@@ -1,5 +1,7 @@
 package smartBank;
 
+import java.util.Random;
+
 public class TransferSpam extends Thread{
         Bank bank;
         Account sender;
@@ -15,19 +17,21 @@ public class TransferSpam extends Thread{
     public void run() {
         for (int i = 0; i < 25; i++) {
             try {
-                Thread.sleep(0);
+                Thread.sleep((int) (Math.random()*500));
             } catch (InterruptedException e) {
                 throw new RuntimeException(e);
             }
 
-            synchronized (Account.getLowerIdAccount(this.sender, this.receiver)){
-                synchronized (Account.getHigherIdAccount(this.sender, this.receiver)){
+            synchronized (bank){ // To make Console prettier? very bad to sync the actual transactions
+            synchronized (Account.getLowerIdAccount(this.sender, this.receiver)) {
+                synchronized (Account.getHigherIdAccount(this.sender, this.receiver)) {
                     bank.transfer(this.sender, this.receiver, 1);
                     System.out.println(bank);
                 }
             }
             }
         }
+    }
 
     public static void main() {
         Bank bank = new Bank();