BAEL-8143 Update Mockito articles

-Mockito version fixes
-MessageMatcher implementation changed as ArugmentMatcher is an Interface now

spring-core/pom.xml

@@ -16,11 +16,6 @@
     </parent>
 
     <dependencies>
-        <dependency>
-            <groupId>org.mockito</groupId>
-            <artifactId>mockito-all</artifactId>
-            <version>${mockito.version}</version>
-        </dependency>
         <dependency>
             <groupId>org.springframework</groupId>
             <artifactId>spring-test</artifactId>
@@ -82,15 +77,7 @@
         </plugins>
     </build>
 
-    <repositories>
-        <repository>
-            <id>java.net</id>
-            <url>https://maven.java.net/content/repositories/releases/</url>
-        </repository>
-    </repositories>
-
     <properties>
-        <mockito.version>2.21.0</mockito.version>
         <mockito.spring.boot.version>1.4.4.RELEASE</mockito.spring.boot.version>
         <javax.inject.version>1</javax.inject.version>
         <guava.version>20.0</guava.version>

spring-mockito/pom.xml

@@ -24,7 +24,7 @@
         </dependency>
         <dependency>
             <groupId>org.mockito</groupId>
-            <artifactId>mockito-all</artifactId>
+            <artifactId>mockito-core</artifactId>
             <version>${mockito.version}</version>
         </dependency>
     </dependencies>

spring-mockito/src/main/java/com/baeldung/domain/util/MessageMatcher.java

@@ -3,7 +3,7 @@ package com.baeldung.domain.util;
 import com.baeldung.domain.model.Message;
 import org.mockito.ArgumentMatcher;
 
-public class MessageMatcher extends ArgumentMatcher<Message> {
+public class MessageMatcher implements ArgumentMatcher<Message> {
 
     private Message left;
 
@@ -12,16 +12,11 @@ public class MessageMatcher extends ArgumentMatcher<Message> {
     }
 
     @Override
-    public boolean matches(Object object) {
-        if (object instanceof Message) {
-            Message right = (Message) object;
-            return left.getFrom().equals(right.getFrom()) &&
-                    left.getTo().equals(right.getTo()) &&
-                    left.getText().equals(right.getText()) &&
-                    right.getDate() != null &&
-                    right.getId() != null;
-        }
-
-        return false;
+    public boolean matches(Message right) {
+        return left.getFrom().equals(right.getFrom()) &&
+          left.getTo().equals(right.getTo()) &&
+          left.getText().equals(right.getText()) &&
+          right.getDate() != null &&
+          right.getId() != null;
     }
 }