diff --git a/core-java/README.md b/core-java/README.md
index 56dee29899..ead65ab166 100644
--- a/core-java/README.md
+++ b/core-java/README.md
@@ -100,3 +100,4 @@
 - [Guide to sun.misc.Unsafe](http://www.baeldung.com/java-unsafe)
 - [HashSet and TreeSet Comparison](http://www.baeldung.com/java-hashset-vs-treeset)
 - [How to Perform a Simple HTTP Request in Java](http://www.baeldung.com/java-http-request)
+- [Call Methods at Runtime Using Java Reflection](http://www.baeldung.com/java-method-reflection)
diff --git a/core-java/src/main/java/com/baeldung/concurrent/phaser/LongRunningAction.java b/core-java/src/main/java/com/baeldung/concurrent/phaser/LongRunningAction.java
new file mode 100644
index 0000000000..dd1487b5cb
--- /dev/null
+++ b/core-java/src/main/java/com/baeldung/concurrent/phaser/LongRunningAction.java
@@ -0,0 +1,27 @@
+package com.baeldung.concurrent.phaser;
+
+import java.util.concurrent.Phaser;
+
+class LongRunningAction implements Runnable {
+    private String threadName;
+    private Phaser ph;
+
+    LongRunningAction(String threadName, Phaser ph) {
+        this.threadName = threadName;
+        this.ph = ph;
+        ph.register();
+    }
+
+    @Override
+    public void run() {
+        System.out.println("This is phase " + ph.getPhase());
+        System.out.println("Thread " + threadName + " before long running action");
+        ph.arriveAndAwaitAdvance();
+        try {
+            Thread.sleep(20);
+        } catch (InterruptedException e) {
+            e.printStackTrace();
+        }
+        ph.arriveAndDeregister();
+    }
+}
\ No newline at end of file
diff --git a/core-java/src/test/java/com/baeldung/concurrent/phaser/PhaserTest.java b/core-java/src/test/java/com/baeldung/concurrent/phaser/PhaserTest.java
new file mode 100644
index 0000000000..7ba1b1ebd9
--- /dev/null
+++ b/core-java/src/test/java/com/baeldung/concurrent/phaser/PhaserTest.java
@@ -0,0 +1,41 @@
+package com.baeldung.concurrent.phaser;
+
+import org.junit.FixMethodOrder;
+import org.junit.Test;
+import org.junit.runners.MethodSorters;
+
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.Phaser;
+
+import static junit.framework.TestCase.assertEquals;
+
+@FixMethodOrder(MethodSorters.NAME_ASCENDING)
+public class PhaserTest {
+
+    @Test
+    public void givenPhaser_whenCoordinateWorksBetweenThreads_thenShouldCoordinateBetweenMultiplePhases() {
+        //given
+        ExecutorService executorService = Executors.newCachedThreadPool();
+        Phaser ph = new Phaser(1);
+        assertEquals(0, ph.getPhase());
+
+        //when
+        executorService.submit(new LongRunningAction("thread-1", ph));
+        executorService.submit(new LongRunningAction("thread-2", ph));
+        executorService.submit(new LongRunningAction("thread-3", ph));
+
+        //then
+        ph.arriveAndAwaitAdvance();
+        assertEquals(1, ph.getPhase());
+
+        //and
+        executorService.submit(new LongRunningAction("thread-4", ph));
+        executorService.submit(new LongRunningAction("thread-5", ph));
+        ph.arriveAndAwaitAdvance();
+        assertEquals(2, ph.getPhase());
+
+
+        ph.arriveAndDeregister();
+    }
+}
diff --git a/core-java/src/test/java/com/baeldung/java/doublebrace/DoubleBraceTest.java b/core-java/src/test/java/com/baeldung/java/doublebrace/DoubleBraceTest.java
index 77d94f6544..531aa8970d 100644
--- a/core-java/src/test/java/com/baeldung/java/doublebrace/DoubleBraceTest.java
+++ b/core-java/src/test/java/com/baeldung/java/doublebrace/DoubleBraceTest.java
@@ -1,18 +1,21 @@
 package com.baeldung.java.doublebrace;
 
+import org.junit.Test;
+
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.Set;
 import java.util.stream.Stream;
+
+import static java.util.stream.Collectors.collectingAndThen;
 import static java.util.stream.Collectors.toSet;
 import static org.junit.Assert.assertTrue;
-import org.junit.Test;
 
 public class DoubleBraceTest {
 
     @Test
     public void whenInitializeSetWithoutDoubleBraces_containsElements() {
-        final Set<String> countries = new HashSet<String>();
+        final Set<String> countries = new HashSet<>();
         countries.add("India");
         countries.add("USSR");
         countries.add("USA");
@@ -34,7 +37,9 @@ public class DoubleBraceTest {
 
     @Test
     public void whenInitializeUnmodifiableSetWithDoubleBrace_containsElements() {
-        final Set<String> countries = Collections.unmodifiableSet(Stream.of("India", "USSR", "USA").collect(toSet()));
+         Set<String> countries = Stream.of("India", "USSR", "USA")
+           .collect(collectingAndThen(toSet(), Collections::unmodifiableSet));
+
         assertTrue(countries.contains("India"));
     }
 
diff --git a/spring-boot/src/main/java/com/baeldung/dynamicvalidation/DynamicValidationApp.java b/spring-boot/src/main/java/com/baeldung/dynamicvalidation/DynamicValidationApp.java
index 361a7b1c03..acdd836c8c 100644
--- a/spring-boot/src/main/java/com/baeldung/dynamicvalidation/DynamicValidationApp.java
+++ b/spring-boot/src/main/java/com/baeldung/dynamicvalidation/DynamicValidationApp.java
@@ -5,7 +5,9 @@ import javax.annotation.security.RolesAllowed;
 import org.springframework.boot.SpringApplication;
 import org.springframework.boot.autoconfigure.SpringBootApplication;
 
-@SpringBootApplication
+import com.baeldung.autoconfiguration.MySQLAutoconfiguration;
+
+@SpringBootApplication(exclude = MySQLAutoconfiguration.class)
 public class DynamicValidationApp {
     @RolesAllowed("*")
     public static void main(String[] args) {