diff --git a/start.java b/threads_test/test_1_start.java
similarity index 94%
rename from start.java
rename to threads_test/test_1_start.java
index adff86f..1737357 100644
--- a/start.java
+++ b/threads_test/test_1_start.java
@@ -1,7 +1,9 @@
+package threads_test;
+
 /**
  * Created by Giovanni on 04/10/2014.
  */
-public class start {
+public class test_1_start {
 
     public static class xthread implements Runnable{
         @Override
diff --git a/threads_test/test_2_singleton.java b/threads_test/test_2_singleton.java
new file mode 100644
index 0000000..1631248
--- /dev/null
+++ b/threads_test/test_2_singleton.java
@@ -0,0 +1,39 @@
+package threads_test;
+
+/**
+ * Created by Giovanni on 12/10/2014.
+ */
+public class test_2_singleton {
+
+    private test_2_singleton(){
+
+        a="initialized";
+
+    }
+
+    private String a;
+
+
+
+
+    //////////////////////////////////////////////////////////////
+
+    private static class inner_test_2_singleton {
+
+
+        private static final test_2_singleton x = new test_2_singleton() ;
+
+    }
+
+
+
+
+    public static test_2_singleton get_instance(){
+
+        return inner_test_2_singleton.x;
+    }
+
+
+
+
+}
diff --git a/threads_test/test_2_start.java b/threads_test/test_2_start.java
new file mode 100644
index 0000000..02c8a94
--- /dev/null
+++ b/threads_test/test_2_start.java
@@ -0,0 +1,22 @@
+package threads_test;
+
+/**
+ * Created by Giovanni on 12/10/2014.
+ */
+public class test_2_start {
+
+    public static void main (String[] args) {
+
+
+        test_2_singleton o= test_2_singleton.get_instance();
+        test_2_singleton o2= test_2_singleton.get_instance();
+
+        if (o == o2 )
+            System.out.print("Equal");
+
+
+    }
+
+
+
+}
diff --git a/threads_test/test_3_start_l.java b/threads_test/test_3_start_l.java
new file mode 100644
index 0000000..120e1f5
--- /dev/null
+++ b/threads_test/test_3_start_l.java
@@ -0,0 +1,63 @@
+package threads_test;
+
+/**
+ * Created by Giovanni on 12/10/2014.
+ */
+public class test_3_start_l {
+
+
+    public static void main (String[] args) {
+
+        class Thread1 implements Runnable{
+
+
+            @Override
+            public void run() {
+                test_3_static_synchronized_lock.op1();
+            }
+        }
+
+        class Thread2 implements Runnable{
+
+
+            @Override
+            public void run() {
+                test_3_static_synchronized_lock.op2();
+            }
+        }
+
+        class Thread3 implements Runnable{
+
+
+            @Override
+            public void run() {
+                test_3_static_synchronized_lock.op3();
+            }
+        }
+
+        Thread a =  new Thread(new Thread1());
+        a.start();
+        Thread b =  new Thread(new Thread2());
+        b.start();
+        Thread c =  new Thread(new Thread3());
+        c.start();
+
+        try {
+            a.join();
+        } catch (InterruptedException e) {
+            e.printStackTrace();
+        }
+        try {
+            b.join();
+        } catch (InterruptedException e) {
+            e.printStackTrace();
+        }
+        try {
+            c.join();
+        } catch (InterruptedException e) {
+            e.printStackTrace();
+        }
+
+
+    }
+}
diff --git a/threads_test/test_3_start_m.java b/threads_test/test_3_start_m.java
new file mode 100644
index 0000000..1a975a6
--- /dev/null
+++ b/threads_test/test_3_start_m.java
@@ -0,0 +1,63 @@
+package threads_test;
+
+/**
+ * Created by Giovanni on 12/10/2014.
+ */
+public class test_3_start_m {
+
+
+    public static void main (String[] args) {
+
+        class Thread1 implements Runnable{
+
+
+            @Override
+            public void run() {
+                test_3_static_synchronized_methods.op1();
+            }
+        }
+
+        class Thread2 implements Runnable{
+
+
+            @Override
+            public void run() {
+                test_3_static_synchronized_methods.op2();
+            }
+        }
+
+        class Thread3 implements Runnable{
+
+
+            @Override
+            public void run() {
+                test_3_static_synchronized_methods.op3();
+            }
+        }
+
+        Thread a =  new Thread(new Thread1());
+        a.start();
+        Thread b =  new Thread(new Thread2());
+        b.start();
+        Thread c =  new Thread(new Thread3());
+        c.start();
+
+        try {
+            a.join();
+        } catch (InterruptedException e) {
+            e.printStackTrace();
+        }
+        try {
+            b.join();
+        } catch (InterruptedException e) {
+            e.printStackTrace();
+        }
+        try {
+            c.join();
+        } catch (InterruptedException e) {
+            e.printStackTrace();
+        }
+
+
+    }
+}
diff --git a/threads_test/test_3_static_synchronized_lock.java b/threads_test/test_3_static_synchronized_lock.java
new file mode 100644
index 0000000..bdaa346
--- /dev/null
+++ b/threads_test/test_3_static_synchronized_lock.java
@@ -0,0 +1,36 @@
+package threads_test;
+
+/**
+ * Created by Giovanni on 12/10/2014.
+ */
+public class test_3_static_synchronized_lock {
+
+    public static  void op1()  {
+        try {
+
+            synchronized (test_3_static_synchronized_lock.class) {
+                Thread.currentThread().sleep(5000);
+                System.out.print("OP1 eseguita");
+            }
+
+
+
+        } catch (InterruptedException e) {
+            e.printStackTrace();
+        }
+    }
+
+    public static  void op2()  {
+        synchronized (test_3_static_synchronized_lock.class) {
+                System.out.print("OP2 eseguita");
+        }
+    }
+
+    public static void op3()  {
+        System.out.print("OP3 eseguita");
+    }
+
+
+
+
+}
diff --git a/threads_test/test_3_static_synchronized_methods.java b/threads_test/test_3_static_synchronized_methods.java
new file mode 100644
index 0000000..3754082
--- /dev/null
+++ b/threads_test/test_3_static_synchronized_methods.java
@@ -0,0 +1,28 @@
+package threads_test;
+
+/**
+ * Created by Giovanni on 12/10/2014.
+ */
+public class test_3_static_synchronized_methods {
+
+    public static synchronized void op1()  {
+        try {
+            Thread.currentThread().sleep(5000);
+            System.out.print("OP1 eseguita");
+        } catch (InterruptedException e) {
+            e.printStackTrace();
+        }
+    }
+
+    public static synchronized void op2()  {
+                System.out.print("OP2 eseguita");
+    }
+
+    public static void op3()  {
+        System.out.print("OP3 eseguita");
+    }
+
+
+
+
+}