Simplify code

src/com/winterbe/java8/samples/concurrent/Lock2.java

@@ -18,13 +18,10 @@ public class Lock2 {
         executor.submit(() -> {
             lock.lock();
             try {
-                System.out.println(lock.isLocked());
                 TimeUnit.SECONDS.sleep(1);
-            }
-            catch (InterruptedException e) {
+            } catch (InterruptedException e) {
                 throw new IllegalStateException(e);
-            }
-            finally {
+            } finally {
                 lock.unlock();
             }
         });

src/com/winterbe/java8/samples/concurrent/Lock3.java

@@ -25,44 +25,26 @@ public class Lock3 {
             try {
                 TimeUnit.SECONDS.sleep(1);
                 map.put("foo", "bar");
-            }
-            catch (InterruptedException e) {
+            } catch (InterruptedException e) {
                 throw new IllegalStateException(e);
-            }
-            finally {
+            } finally {
                 lock.writeLock().unlock();
             }
         });
 
-        executor.submit(() -> {
+        Runnable readTask = () -> {
             lock.readLock().lock();
             try {
-                String foo = map.get("foo");
-                System.out.println(foo);
+                System.out.println(map.get("foo"));
                 TimeUnit.SECONDS.sleep(1);
-            }
-            catch (InterruptedException e) {
+            } catch (InterruptedException e) {
                 throw new IllegalStateException(e);
-            }
-            finally {
+            } finally {
                 lock.readLock().unlock();
             }
-        });
-
-        executor.submit(() -> {
-            lock.readLock().lock();
-            try {
-                String foo = map.get("foo");
-                System.out.println(foo);
-                TimeUnit.SECONDS.sleep(1);
-            }
-            catch (InterruptedException e) {
-                throw new IllegalStateException(e);
-            }
-            finally {
-                lock.readLock().unlock();
-            }
-        });
+        };
+        executor.submit(readTask);
+        executor.submit(readTask);
 
         ConcurrentUtils.stop(executor);
     }

src/com/winterbe/java8/samples/concurrent/Lock4.java

 package com.winterbe.java8.samples.concurrent;
 
+import java.util.HashMap;
+import java.util.Map;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.TimeUnit;
@@ -10,18 +12,18 @@ import java.util.concurrent.locks.StampedLock;
  */
 public class Lock4 {
 
-    private static int count = 0;
-
     public static void main(String[] args) {
         ExecutorService executor = Executors.newFixedThreadPool(2);
 
+        Map<String, String> map = new HashMap<>();
+
         StampedLock lock = new StampedLock();
 
         executor.submit(() -> {
             long stamp = lock.writeLock();
             try {
-                count++;
                 TimeUnit.SECONDS.sleep(1);
+                map.put("foo", "bar");
             } catch (InterruptedException e) {
                 throw new IllegalStateException(e);
             } finally {
@@ -29,29 +31,19 @@ public class Lock4 {
             }
         });
 
-        executor.submit(() -> {
+        Runnable readTask = () -> {
             long stamp = lock.readLock();
             try {
-                System.out.println(Thread.currentThread().getName() + ": " + count);
+                System.out.println(map.get("foo"));
                 TimeUnit.SECONDS.sleep(1);
             } catch (InterruptedException e) {
                 throw new IllegalStateException(e);
             } finally {
                 lock.unlockRead(stamp);
             }
-        });
-
-        executor.submit(() -> {
-            long stamp = lock.readLock();
-            try {
-                System.out.println(Thread.currentThread().getName() + ": " + count);
-                TimeUnit.SECONDS.sleep(1);
-            } catch (InterruptedException e) {
-                throw new IllegalStateException(e);
-            } finally {
-                lock.unlockRead(stamp);
-            }
-        });
+        };
+        executor.submit(readTask);
+        executor.submit(readTask);
 
         ConcurrentUtils.stop(executor);
     }