Added more strings exercises as well as one more advanced OOP one

src/Mainer.java

@@ -4,7 +4,11 @@ public class Mainer {
 
 	public static void main(String[] args) {  // MANDATORY
 
-
+		String a = "sd";
+
+		String b = "sd";
+
+		System.out.println(!a.equals(b));
 	}
 
 

src/loops/test.md

@@ -0,0 +1,3 @@
+### Loops
+
+In class we've see

src/threads/sample/sample1/Mainer.java

@@ -0,0 +1,32 @@
+package threads.sample.sample1;
+
+public class Mainer {
+    public static void main(String[] args) {
+        int num = 10;
+
+        // Create 10 MyThread objects
+        // They will NOT start to run just yet
+        MyThread[] threads = new MyThread[num];
+        for (int i = 0; i < threads.length; i++) {
+            threads[i] = new MyThread();
+        }
+
+        for(MyThread t : threads) {
+            t.start(); // we call start() even though we've overwritten "run()"
+        }
+
+        for(MyThread t : threads) {
+            // the x.join() method will make the caller thread
+            // To wait until the thread 'x' will finish its work
+            try {
+                t.join();   // Prevents the main thread from running
+                // until 't' finishes its work
+            } catch (InterruptedException e) {
+                e.printStackTrace();
+            }
+        }
+
+        System.out.println("Main is done");
+
+    }
+}

src/threads/sample/sample1/MyThread.java

@@ -0,0 +1,28 @@
+package threads.sample.sample1;
+
+/***
+ * Create your own Thread class by extending the java Thread class
+ * Or implementing the Runnable interface.
+ * After doing either of these, you have to override the run() method.
+ * ONLY code inside of the run() method will run on the separate thread
+ *
+ *
+ * For this example we're extending the Thread class
+ */
+public class MyThread extends Thread{
+
+    @Override
+    public void run() {
+        String threadName = Thread.currentThread().getName();
+        System.out.println("Hi there my name is " + threadName);
+
+        try {
+            // Pretend to do extensive work for 2 seconds
+            Thread.sleep(2 * 1000);
+        } catch (InterruptedException e) {
+            e.printStackTrace();
+        }
+
+        System.out.println("Thread: " + threadName + " is done");
+    }
+}

src/threads/sample/sample2/Mainer.java

@@ -0,0 +1,34 @@
+package threads.sample.sample2;
+
+public class Mainer {
+
+    public static void main(String[] args) {
+
+        SharedData sharedData = new SharedData(); // only 1 data object created
+
+
+        // Create 10 MyThread objects
+        // They will NOT start to run just yet
+        MyThread[] threads = new MyThread[2];
+        for (int i = 0; i < threads.length; i++) {
+            threads[i] = new MyThread(sharedData);
+        }
+
+        for(MyThread t : threads) {
+            t.start(); // we call start() even though we've overwritten "run()"
+        }
+
+        for(MyThread t : threads) {
+            // the x.join() method will make the caller thread
+            // To wait until the thread 'x' will finish its work
+            try {
+                t.join();   // Prevents the main thread from running
+                // until 't' finishes its work
+            } catch (InterruptedException e) {
+                e.printStackTrace();
+            }
+        }
+
+        System.out.println("Main is done: " + sharedData.n);
+    }
+}

src/threads/sample/sample2/MyThread.java

@@ -0,0 +1,21 @@
+package threads.sample.sample2;
+
+public class MyThread extends Thread {
+    private SharedData data;
+
+    public MyThread(SharedData data) {
+        this.data = data;
+    }
+
+    @Override
+    public void run() {
+        for (int i =0; i < 50; i++) {
+            // Synchronization happens on the OBJECT
+            synchronized (data) {
+                // Only 1 thread is allowed inside this chunk of code
+                // Incrementation is safe
+                this.data.n++;
+            }
+        }
+    }
+}

src/threads/sample/sample2/SharedData.java

@@ -0,0 +1,14 @@
+package threads.sample.sample2;
+
+public class SharedData {
+    // n is public
+    // and NOT thread safe
+
+    public int n;
+
+    public SharedData() {
+        this.n = 0;
+    }
+
+
+}

src/threads/sample/sample3/Shared.java

@@ -0,0 +1,7 @@
+package threads.sample.sample3;
+
+// not complete yet
+public class Shared {
+
+
+}