Make implicit bidder config defaults more explicit (#1488)

Author: And1sS

src/main/java/org/prebid/server/spring/config/bidder/model/BidderConfigurationProperties.java

@@ -11,7 +11,6 @@
 import javax.annotation.PostConstruct;
 import javax.validation.constraints.NotBlank;
 import javax.validation.constraints.NotNull;
-import java.util.Collections;
 import java.util.List;
 import java.util.Map;
 
@@ -35,17 +34,17 @@ public class BidderConfigurationProperties {
 
     private Boolean modifyingVastXmlAllowed;
 
-    private List<String> deprecatedNames = Collections.emptyList();
+    private List<String> deprecatedNames;
 
-    private Map<String, Object> aliases = Collections.emptyMap();
+    private Map<String, Object> aliases;
 
     @NotNull
     private MetaInfo metaInfo;
 
     @NotNull
     private UsersyncConfigurationProperties usersync;
 
-    private Map<String, String> extraInfo = Collections.emptyMap();
+    private Map<String, String> extraInfo;
 
     private final Class<? extends BidderConfigurationProperties> selfClass;
 
@@ -60,5 +59,8 @@ private void init() {
         pbsEnforcesCcpa = ObjectUtils.defaultIfNull(pbsEnforcesCcpa, defaultProperties.getPbsEnforcesCcpa());
         modifyingVastXmlAllowed = ObjectUtils.defaultIfNull(modifyingVastXmlAllowed,
                 defaultProperties.getModifyingVastXmlAllowed());
+        aliases = ObjectUtils.defaultIfNull(aliases, defaultProperties.getAliases());
+        deprecatedNames = ObjectUtils.defaultIfNull(deprecatedNames, defaultProperties.getDeprecatedNames());
+        extraInfo = ObjectUtils.defaultIfNull(extraInfo, defaultProperties.getExtraInfo());
     }
 }

src/main/java/org/prebid/server/spring/config/bidder/model/DefaultBidderConfigurationProperties.java

@@ -4,6 +4,9 @@
 import org.springframework.validation.annotation.Validated;
 
 import javax.validation.constraints.NotNull;
+import java.util.Collections;
+import java.util.List;
+import java.util.Map;
 
 @Validated
 @Data
@@ -20,4 +23,10 @@ public class DefaultBidderConfigurationProperties {
 
     @NotNull
     private Boolean modifyingVastXmlAllowed;
+
+    private final Map<String, Object> aliases = Collections.emptyMap();
+
+    private final List<String> deprecatedNames = Collections.emptyList();
+
+    private final Map<String, String> extraInfo = Collections.emptyMap();
 }