Continue code tidy-up

Author: nightowlengineer

src/main/java/engineer/nightowl/sonos/api/domain/SonosMetadataStatus.java

@@ -1,10 +1,13 @@
 package engineer.nightowl.sonos.api.domain;
 
+import java.util.Objects;
+
 /**
- * <p>SonosMetadataStatus class.</p>
+ * <p>
+ * SonosMetadataStatus class.
+ * </p>
  */
-public class SonosMetadataStatus
-{
+public class SonosMetadataStatus {
     private SonosMusicContainer container;
     private SonosItem currentItem;
     private SonosItem nextItem;
@@ -55,45 +58,18 @@ public void setStreamInfo(String streamInfo) {
 
     @Override
     public int hashCode() {
-        final int prime = 31;
-        int result = 1;
-        result = prime * result + ((container == null) ? 0 : container.hashCode());
-        result = prime * result + ((currentItem == null) ? 0 : currentItem.hashCode());
-        result = prime * result + ((nextItem == null) ? 0 : nextItem.hashCode());
-        result = prime * result + ((streamInfo == null) ? 0 : streamInfo.hashCode());
-        return result;
+        return Objects.hash(container, currentItem, nextItem, streamInfo);
     }
 
     @Override
     public boolean equals(Object obj) {
         if (this == obj)
             return true;
-        if (obj == null)
-            return false;
-        if (getClass() != obj.getClass())
+        if (!(obj instanceof SonosMetadataStatus))
             return false;
         SonosMetadataStatus other = (SonosMetadataStatus) obj;
-        if (container == null) {
-            if (other.container != null)
-                return false;
-        } else if (!container.equals(other.container))
-            return false;
-        if (currentItem == null) {
-            if (other.currentItem != null)
-                return false;
-        } else if (!currentItem.equals(other.currentItem))
-            return false;
-        if (nextItem == null) {
-            if (other.nextItem != null)
-                return false;
-        } else if (!nextItem.equals(other.nextItem))
-            return false;
-        if (streamInfo == null) {
-            if (other.streamInfo != null)
-                return false;
-        } else if (!streamInfo.equals(other.streamInfo))
-            return false;
-        return true;
+        return Objects.equals(container, other.container) && Objects.equals(currentItem, other.currentItem)
+                && Objects.equals(nextItem, other.nextItem) && Objects.equals(streamInfo, other.streamInfo);
     }
 
     @Override

src/main/java/engineer/nightowl/sonos/api/resource/AuthorizeResource.java

@@ -27,7 +27,7 @@
 public class AuthorizeResource extends BaseResource
 {
 
-    private final String HTTPS = "https";
+    private static final String HTTPS = "https";
 
     /**
      * <p>Constructor for AuthorizeResource.</p>

src/main/java/engineer/nightowl/sonos/api/resource/PlayerVolumeResource.java

@@ -17,7 +17,7 @@
  */
 public class PlayerVolumeResource extends SubscribableResource
 {
-    private final String MUTED = "muted";
+    private static final String MUTED = "muted";
     /**
      * <p>Constructor for PlayerVolumeResource.</p>
      *