From 769d65f009fcb8434aeded565e7bdd4d33ed364f Mon Sep 17 00:00:00 2001
From: Roy Clarkson <rclarkson@pivotal.io>
Date: Fri, 29 Mar 2019 10:20:33 -0400
Subject: [PATCH] Protect against possible NullPointerException when building
 collections

---
 .../deployer/BackingApplication.java          | 109 +++++++++++++-----
 .../deployer/BackingApplications.java         |  13 +--
 .../appbroker/deployer/BackingService.java    |  51 ++++----
 .../appbroker/deployer/BackingServices.java   |  20 +++-
 .../appbroker/deployer/BrokeredService.java   |  14 ++-
 .../appbroker/deployer/BrokeredServices.java  |  13 ++-
 .../deployer/CredentialProviderSpec.java      |  21 ++--
 .../deployer/ParametersTransformerSpec.java   |  26 +++--
 .../appbroker/deployer/ServicesSpec.java      |  12 +-
 .../cloud/appbroker/deployer/TargetSpec.java  |   4 -
 .../extensions/targets/ArtifactDetails.java   |   7 +-
 .../AppDeploymentInstanceWorkflow.java        |  19 ++-
 .../deployer/DeployerClientTest.java          |   4 +-
 .../CreateServiceInstanceRequest.java         |  16 +--
 .../DeleteServiceInstanceRequest.java         |   9 +-
 .../deployer/DeployApplicationRequest.java    |  28 +++--
 .../deployer/UndeployApplicationRequest.java  |   9 +-
 .../deployer/UpdateApplicationRequest.java    |  28 +++--
 .../UpdateServiceInstanceRequest.java         |  16 +--
 .../oauth2/CreateOAuth2ClientRequest.java     |  19 ++-
 .../oauth2/CreateOAuth2ClientResponse.java    |  21 +++-
 .../oauth2/DeleteOAuth2ClientResponse.java    |  21 +++-
 22 files changed, 325 insertions(+), 155 deletions(-)

diff --git a/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/deployer/BackingApplication.java b/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/deployer/BackingApplication.java
index c001d36..0b619d6 100644
--- a/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/deployer/BackingApplication.java
+++ b/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/deployer/BackingApplication.java
@@ -24,6 +24,9 @@ import java.util.Map;
 import java.util.Objects;
 import java.util.stream.Collectors;
 
+import org.springframework.util.CollectionUtils;
+
+@SuppressWarnings("PMD.GodClass")
 public class BackingApplication {
 
 	private static final String VALUE_HIDDEN = "<value hidden>";
@@ -36,26 +39,6 @@ public class BackingApplication {
 	private List<ParametersTransformerSpec> parametersTransformers;
 	private List<CredentialProviderSpec> credentialProviders;
 
-	public BackingApplication(BackingApplication backingApplicationToCopy) {
-		this.name = backingApplicationToCopy.name;
-		this.path = backingApplicationToCopy.path;
-		this.properties = backingApplicationToCopy.properties == null
-			? new HashMap<>()
-			: new HashMap<>(backingApplicationToCopy.properties);
-		this.environment = backingApplicationToCopy.environment == null
-			? new HashMap<>()
-			: new HashMap<>(backingApplicationToCopy.environment);
-		this.services = backingApplicationToCopy.services == null
-			? new ArrayList<>()
-			: backingApplicationToCopy.services.stream().map(ServicesSpec::new).collect(Collectors.toList());
-		this.parametersTransformers = backingApplicationToCopy.parametersTransformers == null
-			? new ArrayList<>()
-			: backingApplicationToCopy.parametersTransformers.stream().map(ParametersTransformerSpec::new).collect(Collectors.toList());
-		this.credentialProviders = backingApplicationToCopy.credentialProviders == null
-			? new ArrayList<>()
-			: backingApplicationToCopy.credentialProviders.stream().map(CredentialProviderSpec::new).collect(Collectors.toList());
-	}
-
 	private BackingApplication() {
 	}
 
@@ -193,16 +176,51 @@ public class BackingApplication {
 	public static class BackingApplicationBuilder {
 
 		private String name;
+
 		private String path;
+
 		private final Map<String, String> properties = new HashMap<>();
+
 		private final Map<String, Object> environment = new HashMap<>();
+
 		private final List<ServicesSpec> services = new ArrayList<>();
+
 		private final List<ParametersTransformerSpec> parameterTransformers = new ArrayList<>();
+
 		private final List<CredentialProviderSpec> credentialProviders = new ArrayList<>();
 
 		BackingApplicationBuilder() {
 		}
 
+		public BackingApplicationBuilder backingApplication(BackingApplication backingApplication) {
+			this.name(backingApplication.getName())
+				.path(backingApplication.getPath())
+				.properties(backingApplication.getProperties())
+				.environment(backingApplication.getEnvironment());
+				if (!CollectionUtils.isEmpty(backingApplication.getServices())) {
+					this.services(backingApplication.getServices().stream()
+						.map(spec -> ServicesSpec.builder()
+							.spec(spec)
+							.build())
+						.collect(Collectors.toList()));
+				}
+				if (!CollectionUtils.isEmpty(backingApplication.getParametersTransformers())) {
+					this.parameterTransformers(backingApplication.getParametersTransformers().stream()
+						.map(spec -> ParametersTransformerSpec.builder()
+							.spec(spec)
+							.build())
+						.collect(Collectors.toList()));
+				}
+				if (!CollectionUtils.isEmpty(backingApplication.getCredentialProviders())) {
+					this.credentialProviders(backingApplication.getCredentialProviders().stream()
+						.map(spec -> CredentialProviderSpec.builder()
+							.spec(spec)
+							.build())
+						.collect(Collectors.toList()));
+				}
+				return this;
+		}
+
 		public BackingApplicationBuilder name(String name) {
 			this.name = name;
 			return this;
@@ -214,37 +232,72 @@ public class BackingApplication {
 		}
 
 		public BackingApplicationBuilder property(String key, String value) {
-			this.properties.put(key, value);
+			if (key != null && value != null) {
+				this.properties.put(key, value);
+			}
 			return this;
 		}
 
 		public BackingApplicationBuilder properties(Map<String, String> properties) {
-			this.properties.putAll(properties);
+			if (!CollectionUtils.isEmpty(properties)) {
+				this.properties.putAll(properties);
+			}
 			return this;
 		}
 
 		public BackingApplicationBuilder environment(String key, String value) {
-			this.environment.put(key, value);
+			if (key != null && value != null) {
+				this.environment.put(key, value);
+			}
 			return this;
 		}
 
-		public BackingApplicationBuilder environment(Map<String, String> environment) {
-			this.environment.putAll(environment);
+		public BackingApplicationBuilder environment(Map<String, Object> environment) {
+			if (!CollectionUtils.isEmpty(environment)) {
+				this.environment.putAll(environment);
+			}
+			return this;
+		}
+
+		public BackingApplicationBuilder services(List<ServicesSpec> services) {
+			if (!CollectionUtils.isEmpty(services)) {
+				this.services.addAll(services);
+			}
 			return this;
 		}
 
 		public BackingApplicationBuilder services(ServicesSpec... services) {
-			this.services.addAll(Arrays.asList(services));
+			if (services != null) {
+				this.services(Arrays.asList(services));
+			}
+			return this;
+		}
+
+		public BackingApplicationBuilder parameterTransformers(List<ParametersTransformerSpec> parameterTransformers) {
+			if (!CollectionUtils.isEmpty(parameterTransformers)) {
+				this.parameterTransformers.addAll(parameterTransformers);
+			}
 			return this;
 		}
 
 		public BackingApplicationBuilder parameterTransformers(ParametersTransformerSpec... parameterTransformers) {
-			this.parameterTransformers.addAll(Arrays.asList(parameterTransformers));
+			if (parameterTransformers != null) {
+				this.parameterTransformers(Arrays.asList(parameterTransformers));
+			}
+			return this;
+		}
+
+		public BackingApplicationBuilder credentialProviders(List<CredentialProviderSpec> credentialProviders) {
+			if (!CollectionUtils.isEmpty(credentialProviders)) {
+				this.credentialProviders.addAll(credentialProviders);
+			}
 			return this;
 		}
 
 		public BackingApplicationBuilder credentialProviders(CredentialProviderSpec... credentialProviders) {
-			this.credentialProviders.addAll(Arrays.asList(credentialProviders));
+			if (credentialProviders != null) {
+				this.credentialProviders(Arrays.asList(credentialProviders));
+			}
 			return this;
 		}
 
diff --git a/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/deployer/BackingApplications.java b/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/deployer/BackingApplications.java
index 7d5c37d..6b7c27d 100644
--- a/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/deployer/BackingApplications.java
+++ b/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/deployer/BackingApplications.java
@@ -31,11 +31,6 @@ public class BackingApplications extends ArrayList<BackingApplication> {
 		super.addAll(backingApplications);
 	}
 
-	public BackingApplications(BackingApplications backingApplicationsToCopy) {
-		backingApplicationsToCopy.forEach(backingApplicationToCopy ->
-			this.add(new BackingApplication(backingApplicationToCopy)));
-	}
-
 	public static BackingApplicationsBuilder builder() {
 		return new BackingApplicationsBuilder();
 	}
@@ -44,13 +39,17 @@ public class BackingApplications extends ArrayList<BackingApplication> {
 		private final List<BackingApplication> backingApplications = new ArrayList<>();
 
 		public BackingApplicationsBuilder backingApplication(BackingApplication backingApplication) {
-			this.backingApplications.add(backingApplication);
+			if (backingApplication != null) {
+				this.backingApplications.add(backingApplication);
+			}
 			return this;
 		}
 
 		public BackingApplicationsBuilder backingApplications(List<BackingApplication> backingApplications) {
 			if (!CollectionUtils.isEmpty(backingApplications)) {
-				this.backingApplications.addAll(backingApplications);
+				backingApplications.forEach(backingApplication -> this.backingApplication(BackingApplication.builder()
+					.backingApplication(backingApplication)
+					.build()));
 			}
 			return this;
 		}
diff --git a/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/deployer/BackingService.java b/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/deployer/BackingService.java
index 18d3f47..570a5f0 100644
--- a/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/deployer/BackingService.java
+++ b/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/deployer/BackingService.java
@@ -23,6 +23,8 @@ import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 
+import org.springframework.util.CollectionUtils;
+
 public class BackingService {
 
 	private String serviceInstanceName;
@@ -52,22 +54,6 @@ public class BackingService {
 		this.rebindOnUpdate = rebindOnUpdate;
 	}
 
-	BackingService(BackingService backingServiceToCopy) {
-		this.serviceInstanceName = backingServiceToCopy.serviceInstanceName;
-		this.name = backingServiceToCopy.name;
-		this.plan = backingServiceToCopy.plan;
-		this.parameters = backingServiceToCopy.parameters == null
-			? new HashMap<>()
-			: new HashMap<>(backingServiceToCopy.parameters);
-		this.properties = backingServiceToCopy.properties == null
-			? new HashMap<>()
-			: new HashMap<>(backingServiceToCopy.properties);
-		this.parametersTransformers = backingServiceToCopy.parametersTransformers == null
-			? new ArrayList<>()
-			: new ArrayList<>(backingServiceToCopy.parametersTransformers);
-		this.rebindOnUpdate = backingServiceToCopy.rebindOnUpdate;
-	}
-
 	public String getServiceInstanceName() {
 		return serviceInstanceName;
 	}
@@ -171,14 +157,24 @@ public class BackingService {
 		private String serviceInstanceName;
 		private String name;
 		private String plan;
-		private Map<String, Object> parameters = new HashMap<>();
-		private Map<String, String> properties = new HashMap<>();
+		private final Map<String, Object> parameters = new HashMap<>();
+		private final Map<String, String> properties = new HashMap<>();
 		private final List<ParametersTransformerSpec> parameterTransformers = new ArrayList<>();
 		private boolean rebindOnUpdate;
 
 		BackingServiceBuilder() {
 		}
 
+		public BackingServiceBuilder backingService(BackingService backingService) {
+			return this.serviceInstanceName(backingService.getServiceInstanceName())
+				.name(backingService.getName())
+				.plan(backingService.getPlan())
+				.parameters(backingService.getParameters())
+				.properties(backingService.getProperties())
+				.parameterTransformers(backingService.getParametersTransformers())
+				.rebindOnUpdate(backingService.isRebindOnUpdate());
+		}
+
 		public BackingServiceBuilder serviceInstanceName(String serviceInstanceName) {
 			this.serviceInstanceName = serviceInstanceName;
 			return this;
@@ -195,17 +191,30 @@ public class BackingService {
 		}
 
 		public BackingServiceBuilder parameters(Map<String, Object> parameters) {
-			this.parameters = parameters;
+			if (!CollectionUtils.isEmpty(parameters)) {
+				this.parameters.putAll(parameters);
+			}
 			return this;
 		}
 
 		public BackingServiceBuilder properties(Map<String, String> properties) {
-			this.properties = properties;
+			if (!CollectionUtils.isEmpty(properties)) {
+				this.properties.putAll(properties);
+			}
+			return this;
+		}
+
+		public BackingServiceBuilder parameterTransformers(List<ParametersTransformerSpec> parameterTransformers) {
+			if (!CollectionUtils.isEmpty(parameterTransformers)) {
+				this.parameterTransformers.addAll(parameterTransformers);
+			}
 			return this;
 		}
 
 		public BackingServiceBuilder parameterTransformers(ParametersTransformerSpec... parameterTransformers) {
-			this.parameterTransformers.addAll(Arrays.asList(parameterTransformers));
+			if (parameterTransformers != null) {
+				this.parameterTransformers(Arrays.asList(parameterTransformers));
+			}
 			return this;
 		}
 
diff --git a/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/deployer/BackingServices.java b/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/deployer/BackingServices.java
index 3128def..69d18a6 100644
--- a/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/deployer/BackingServices.java
+++ b/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/deployer/BackingServices.java
@@ -19,6 +19,8 @@ package org.springframework.cloud.appbroker.deployer;
 import java.util.ArrayList;
 import java.util.List;
 
+import org.springframework.util.CollectionUtils;
+
 public class BackingServices extends ArrayList<BackingService> {
 
 	private static final long serialVersionUID = 1L;
@@ -30,11 +32,6 @@ public class BackingServices extends ArrayList<BackingService> {
 		super.addAll(backingServices);
 	}
 
-	public BackingServices(BackingServices backingServicesToCopy) {
-		backingServicesToCopy.forEach(backingServiceToCopy ->
-			this.add(new BackingService(backingServiceToCopy)));
-	}
-
 	public static BackingServicesBuilder builder() {
 		return new BackingServicesBuilder();
 	}
@@ -44,7 +41,18 @@ public class BackingServices extends ArrayList<BackingService> {
 		private final List<BackingService> backingServices = new ArrayList<>();
 
 		public BackingServicesBuilder backingService(BackingService backingService) {
-			this.backingServices.add(backingService);
+			if (backingService != null) {
+				this.backingServices.add(backingService);
+			}
+			return this;
+		}
+
+		public BackingServicesBuilder backingServices(BackingServices backingServices) {
+			if (!CollectionUtils.isEmpty(backingServices)) {
+				backingServices.forEach(backingService -> this.backingService(BackingService.builder()
+					.backingService(backingService)
+					.build()));
+			}
 			return this;
 		}
 
diff --git a/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/deployer/BrokeredService.java b/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/deployer/BrokeredService.java
index 266faf3..e94feb1 100644
--- a/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/deployer/BrokeredService.java
+++ b/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/deployer/BrokeredService.java
@@ -18,6 +18,8 @@ package org.springframework.cloud.appbroker.deployer;
 
 import java.util.Objects;
 
+import org.springframework.util.CollectionUtils;
+
 public class BrokeredService {
 
 	private String serviceName;
@@ -132,12 +134,20 @@ public class BrokeredService {
 		}
 
 		public BrokeredServiceBuilder apps(BackingApplications backingApplications) {
-			this.backingApplications = backingApplications;
+			if (!CollectionUtils.isEmpty(backingApplications)) {
+				this.backingApplications = BackingApplications.builder()
+					.backingApplications(backingApplications)
+					.build();
+			}
 			return this;
 		}
 
 		public BrokeredServiceBuilder services(BackingServices backingServices) {
-			this.backingServices = backingServices;
+			if (!CollectionUtils.isEmpty(backingServices)) {
+				this.backingServices = BackingServices.builder()
+					.backingServices(backingServices)
+					.build();
+			}
 			return this;
 		}
 
diff --git a/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/deployer/BrokeredServices.java b/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/deployer/BrokeredServices.java
index 6a26974..806de9c 100644
--- a/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/deployer/BrokeredServices.java
+++ b/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/deployer/BrokeredServices.java
@@ -19,6 +19,8 @@ package org.springframework.cloud.appbroker.deployer;
 import java.util.ArrayList;
 import java.util.List;
 
+import org.springframework.util.CollectionUtils;
+
 public class BrokeredServices extends ArrayList<BrokeredService> {
 	private static final long serialVersionUID = 6303127383252611352L;
 
@@ -37,7 +39,16 @@ public class BrokeredServices extends ArrayList<BrokeredService> {
 		private final List<BrokeredService> brokeredServices = new ArrayList<>();
 
 		public BrokeredServicesBuilder service(BrokeredService brokeredService) {
-			this.brokeredServices.add(brokeredService);
+			if (brokeredService != null) {
+				this.brokeredServices.add(brokeredService);
+			}
+			return this;
+		}
+
+		public BrokeredServicesBuilder services(BrokeredServices brokeredServices) {
+			if (!CollectionUtils.isEmpty(brokeredServices)) {
+				this.brokeredServices.addAll(brokeredServices);
+			}
 			return this;
 		}
 
diff --git a/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/deployer/CredentialProviderSpec.java b/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/deployer/CredentialProviderSpec.java
index f78204d..65707ab 100644
--- a/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/deployer/CredentialProviderSpec.java
+++ b/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/deployer/CredentialProviderSpec.java
@@ -19,6 +19,8 @@ package org.springframework.cloud.appbroker.deployer;
 import java.util.LinkedHashMap;
 import java.util.Map;
 
+import org.springframework.util.CollectionUtils;
+
 public class CredentialProviderSpec {
 
 	private String name;
@@ -32,11 +34,6 @@ public class CredentialProviderSpec {
 		this.args = args;
 	}
 
-	CredentialProviderSpec(CredentialProviderSpec credentialProviderSpecToClone) {
-		this.name = credentialProviderSpecToClone.name;
-		this.args = credentialProviderSpecToClone.args;
-	}
-
 	public String getName() {
 		return name;
 	}
@@ -60,23 +57,33 @@ public class CredentialProviderSpec {
 	public static class CredentialProviderSpecBuilder {
 
 		private String name;
+
 		private final Map<String, Object> args = new LinkedHashMap<>();
 
 		CredentialProviderSpecBuilder() {
 		}
 
+		public CredentialProviderSpecBuilder spec(CredentialProviderSpec spec) {
+			return this.name(spec.getName())
+				.args(spec.getArgs());
+		}
+
 		public CredentialProviderSpecBuilder name(String name) {
 			this.name = name;
 			return this;
 		}
 
 		public CredentialProviderSpecBuilder arg(String key, Object value) {
-			this.args.put(key, value);
+			if (key != null && value != null) {
+				this.args.put(key, value);
+			}
 			return this;
 		}
 
 		public CredentialProviderSpecBuilder args(Map<String, Object> args) {
-			this.args.putAll(args);
+			if (!CollectionUtils.isEmpty(args)) {
+				this.args.putAll(args);
+			}
 			return this;
 		}
 
diff --git a/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/deployer/ParametersTransformerSpec.java b/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/deployer/ParametersTransformerSpec.java
index a3fd53f..3358f4a 100644
--- a/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/deployer/ParametersTransformerSpec.java
+++ b/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/deployer/ParametersTransformerSpec.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2018 the original author or authors.
+ * Copyright 2016-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -19,8 +19,12 @@ package org.springframework.cloud.appbroker.deployer;
 import java.util.LinkedHashMap;
 import java.util.Map;
 
+import org.springframework.util.CollectionUtils;
+
 public class ParametersTransformerSpec {
+
 	private String name;
+
 	private Map<String, Object> args;
 
 	private ParametersTransformerSpec() {
@@ -31,11 +35,6 @@ public class ParametersTransformerSpec {
 		this.args = args;
 	}
 
-	ParametersTransformerSpec(ParametersTransformerSpec parametersTransformerSpecToClone) {
-		this.name = parametersTransformerSpecToClone.name;
-		this.args = parametersTransformerSpecToClone.args;
-	}
-
 	public String getName() {
 		return name;
 	}
@@ -57,24 +56,35 @@ public class ParametersTransformerSpec {
 	}
 
 	public static class ParametersTransformerSpecBuilder {
+
 		private String name;
+
 		private final Map<String, Object> args = new LinkedHashMap<>();
 
 		ParametersTransformerSpecBuilder() {
 		}
 
+		public ParametersTransformerSpecBuilder spec(ParametersTransformerSpec spec) {
+			return this.name(spec.getName())
+				.args(spec.getArgs());
+		}
+
 		public ParametersTransformerSpecBuilder name(String name) {
 			this.name = name;
 			return this;
 		}
 
 		public ParametersTransformerSpecBuilder arg(String key, Object value) {
-			this.args.put(key, value);
+			if (key != null && value != null) {
+				this.args.put(key, value);
+			}
 			return this;
 		}
 
 		public ParametersTransformerSpecBuilder args(Map<String, Object> args) {
-			this.args.putAll(args);
+			if (!CollectionUtils.isEmpty(args)) {
+				this.args.putAll(args);
+			}
 			return this;
 		}
 
diff --git a/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/deployer/ServicesSpec.java b/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/deployer/ServicesSpec.java
index 1f301c3..19deada 100644
--- a/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/deployer/ServicesSpec.java
+++ b/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/deployer/ServicesSpec.java
@@ -1,5 +1,5 @@
 /*
- * Copyright 2016-2018 the original author or authors.
+ * Copyright 2016-2019 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -23,10 +23,6 @@ public class ServicesSpec {
 	private ServicesSpec() {
 	}
 
-	ServicesSpec(ServicesSpec servicesSpecToClone) {
-		this.serviceInstanceName = servicesSpecToClone.serviceInstanceName;
-	}
-
 	ServicesSpec(String serviceInstanceName) {
 		this.serviceInstanceName = serviceInstanceName;
 	}
@@ -50,7 +46,11 @@ public class ServicesSpec {
 		ServicesSpecBuilder() {
 		}
 
-		ServicesSpecBuilder serviceInstanceName(String serviceInstanceName) {
+		public ServicesSpecBuilder spec(ServicesSpec spec) {
+			return this.serviceInstanceName(spec.getServiceInstanceName());
+		}
+
+		public ServicesSpecBuilder serviceInstanceName(String serviceInstanceName) {
 			this.serviceInstanceName = serviceInstanceName;
 			return this;
 		}
diff --git a/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/deployer/TargetSpec.java b/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/deployer/TargetSpec.java
index 95a2046..9e634a1 100644
--- a/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/deployer/TargetSpec.java
+++ b/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/deployer/TargetSpec.java
@@ -27,10 +27,6 @@ public class TargetSpec {
 		this.name = name;
 	}
 
-	TargetSpec(TargetSpec targetSpecToClone) {
-		this.name = targetSpecToClone.name;
-	}
-
 	public String getName() {
 		return name;
 	}
diff --git a/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/extensions/targets/ArtifactDetails.java b/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/extensions/targets/ArtifactDetails.java
index 1ee2368..b0082c5 100644
--- a/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/extensions/targets/ArtifactDetails.java
+++ b/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/extensions/targets/ArtifactDetails.java
@@ -19,6 +19,8 @@ package org.springframework.cloud.appbroker.extensions.targets;
 import java.util.HashMap;
 import java.util.Map;
 
+import org.springframework.util.CollectionUtils;
+
 public class ArtifactDetails {
 
 	private final String name;
@@ -55,10 +57,9 @@ public class ArtifactDetails {
 		}
 
 		public ArtifactDetailsBuilder properties(Map<String, String> properties) {
-			if (properties == null) {
-				return this;
+			if (!CollectionUtils.isEmpty(properties)) {
+				this.properties.putAll(properties);
 			}
-			this.properties.putAll(properties);
 			return this;
 		}
 
diff --git a/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/workflow/instance/AppDeploymentInstanceWorkflow.java b/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/workflow/instance/AppDeploymentInstanceWorkflow.java
index 341f744..4d1bb97 100644
--- a/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/workflow/instance/AppDeploymentInstanceWorkflow.java
+++ b/spring-cloud-app-broker-core/src/main/java/org/springframework/cloud/appbroker/workflow/instance/AppDeploymentInstanceWorkflow.java
@@ -29,6 +29,7 @@ import org.springframework.cloud.appbroker.deployer.BrokeredServices;
 import org.springframework.cloud.appbroker.deployer.TargetSpec;
 import org.springframework.cloud.servicebroker.model.catalog.Plan;
 import org.springframework.cloud.servicebroker.model.catalog.ServiceDefinition;
+import org.springframework.util.CollectionUtils;
 
 class AppDeploymentInstanceWorkflow {
 
@@ -63,15 +64,25 @@ class AppDeploymentInstanceWorkflow {
 	private BackingApplications findBackingApplications(ServiceDefinition serviceDefinition,
 														Plan plan) {
 		BrokeredService brokeredService = findBrokeredService(serviceDefinition, plan);
-		return brokeredService == null ? null : new BackingApplications(brokeredService.getApps());
+		BackingApplications backingApplications = null;
+		if (brokeredService != null) {
+			backingApplications = BackingApplications.builder()
+				.backingApplications(brokeredService.getApps())
+				.build();
+		}
+		return backingApplications;
 	}
 
 	private BackingServices findBackingServices(ServiceDefinition serviceDefinition,
 												Plan plan) {
 		BrokeredService brokeredService = findBrokeredService(serviceDefinition, plan);
-		return brokeredService == null || brokeredService.getServices() == null
-			? null
-			: new BackingServices(brokeredService.getServices());
+		BackingServices backingServices = null;
+		if (brokeredService != null && !CollectionUtils.isEmpty(brokeredService.getServices())) {
+			backingServices = BackingServices.builder()
+				.backingServices(brokeredService.getServices())
+				.build();
+		}
+		return backingServices;
 	}
 
 	private BrokeredService findBrokeredService(ServiceDefinition serviceDefinition,
diff --git a/spring-cloud-app-broker-core/src/test/java/org/springframework/cloud/appbroker/deployer/DeployerClientTest.java b/spring-cloud-app-broker-core/src/test/java/org/springframework/cloud/appbroker/deployer/DeployerClientTest.java
index e11a824..e740837 100644
--- a/spring-cloud-app-broker-core/src/test/java/org/springframework/cloud/appbroker/deployer/DeployerClientTest.java
+++ b/spring-cloud-app-broker-core/src/test/java/org/springframework/cloud/appbroker/deployer/DeployerClientTest.java
@@ -135,7 +135,7 @@ class DeployerClientTest {
 		// given
 		setupAppDeployer();
 
-		Map<String, String> environment = new HashMap<String, String>() {{
+		Map<String, Object> environment = new HashMap<String, Object>() {{
 			put("ENV_VAR_1", "value1");
 			put("ENV_VAR_2", "value2");
 		}};
@@ -305,7 +305,7 @@ class DeployerClientTest {
 
 	private ArgumentMatcher<DeployApplicationRequest> matchesRequest(String appName, String appArchive,
 																	 Map<String, String> properties,
-																	 Map<String, String> environment,
+																	 Map<String, Object> environment,
 																	 List<String> services) {
 		return request ->
 			request.getName().equals(appName) &&
diff --git a/spring-cloud-app-broker-deployer/src/main/java/org/springframework/cloud/appbroker/deployer/CreateServiceInstanceRequest.java b/spring-cloud-app-broker-deployer/src/main/java/org/springframework/cloud/appbroker/deployer/CreateServiceInstanceRequest.java
index aebc9da..2688b99 100644
--- a/spring-cloud-app-broker-deployer/src/main/java/org/springframework/cloud/appbroker/deployer/CreateServiceInstanceRequest.java
+++ b/spring-cloud-app-broker-deployer/src/main/java/org/springframework/cloud/appbroker/deployer/CreateServiceInstanceRequest.java
@@ -19,6 +19,8 @@ package org.springframework.cloud.appbroker.deployer;
 import java.util.HashMap;
 import java.util.Map;
 
+import org.springframework.util.CollectionUtils;
+
 public class CreateServiceInstanceRequest {
 
 	private final String serviceInstanceName;
@@ -90,23 +92,23 @@ public class CreateServiceInstanceRequest {
 		}
 
 		public CreateServiceInstanceRequestBuilder parameters(String key, String value) {
-			this.parameters.put(key, value);
+			if (key != null && value != null) {
+				this.parameters.put(key, value);
+			}
 			return this;
 		}
 
 		public CreateServiceInstanceRequestBuilder parameters(Map<String, Object> parameters) {
-			if (parameters == null) {
-				return this;
+			if (!CollectionUtils.isEmpty(parameters)) {
+				this.parameters.putAll(parameters);
 			}
-			this.parameters.putAll(parameters);
 			return this;
 		}
 
 		public CreateServiceInstanceRequestBuilder properties(Map<String, String> properties) {
-			if (properties == null) {
-				return this;
+			if (!CollectionUtils.isEmpty(properties)) {
+				this.properties.putAll(properties);
 			}
-			this.properties.putAll(properties);
 			return this;
 		}
 
diff --git a/spring-cloud-app-broker-deployer/src/main/java/org/springframework/cloud/appbroker/deployer/DeleteServiceInstanceRequest.java b/spring-cloud-app-broker-deployer/src/main/java/org/springframework/cloud/appbroker/deployer/DeleteServiceInstanceRequest.java
index b15c689..2c134d7 100644
--- a/spring-cloud-app-broker-deployer/src/main/java/org/springframework/cloud/appbroker/deployer/DeleteServiceInstanceRequest.java
+++ b/spring-cloud-app-broker-deployer/src/main/java/org/springframework/cloud/appbroker/deployer/DeleteServiceInstanceRequest.java
@@ -16,8 +16,11 @@
 
 package org.springframework.cloud.appbroker.deployer;
 
+import java.util.HashMap;
 import java.util.Map;
 
+import org.springframework.util.CollectionUtils;
+
 public class DeleteServiceInstanceRequest {
 
 	private final String serviceInstanceName;
@@ -43,7 +46,7 @@ public class DeleteServiceInstanceRequest {
 	public static class DeleteServiceInstanceRequestBuilder {
 
 		private String serviceInstanceName;
-		private Map<String, String> properties;
+		private final Map<String, String> properties = new HashMap<>();
 
 		DeleteServiceInstanceRequestBuilder() {
 		}
@@ -54,7 +57,9 @@ public class DeleteServiceInstanceRequest {
 		}
 
 		public DeleteServiceInstanceRequestBuilder properties(Map<String, String> properties) {
-			this.properties = properties;
+			if (!CollectionUtils.isEmpty(properties)) {
+				this.properties.putAll(properties);
+			}
 			return this;
 		}
 
diff --git a/spring-cloud-app-broker-deployer/src/main/java/org/springframework/cloud/appbroker/deployer/DeployApplicationRequest.java b/spring-cloud-app-broker-deployer/src/main/java/org/springframework/cloud/appbroker/deployer/DeployApplicationRequest.java
index f65092d..f74a92b 100644
--- a/spring-cloud-app-broker-deployer/src/main/java/org/springframework/cloud/appbroker/deployer/DeployApplicationRequest.java
+++ b/spring-cloud-app-broker-deployer/src/main/java/org/springframework/cloud/appbroker/deployer/DeployApplicationRequest.java
@@ -21,6 +21,8 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
+import org.springframework.util.CollectionUtils;
+
 public class DeployApplicationRequest {
 
 	private final String name;
@@ -97,38 +99,44 @@ public class DeployApplicationRequest {
 		}
 
 		public DeployApplicationRequestBuilder property(String key, String value) {
-			this.properties.put(key, value);
+			if (key != null && value != null) {
+				this.properties.put(key, value);
+			}
 			return this;
 		}
 
 		public DeployApplicationRequestBuilder properties(Map<String, String> properties) {
-			if (properties == null) {
-				return this;
+			if (!CollectionUtils.isEmpty(properties)) {
+				this.properties.putAll(properties);
 			}
-			this.properties.putAll(properties);
 			return this;
 		}
 
 		public DeployApplicationRequestBuilder environment(String key, String value) {
-			this.environment.put(key, value);
+			if (key != null && value != null) {
+				this.environment.put(key, value);
+			}
 			return this;
 		}
 
 		public DeployApplicationRequestBuilder environment(Map<String, Object> environment) {
-			if (environment == null) {
-				return this;
+			if (!CollectionUtils.isEmpty(environment)) {
+				this.environment.putAll(environment);
 			}
-			this.environment.putAll(environment);
 			return this;
 		}
 
 		public DeployApplicationRequestBuilder service(String service) {
-			this.services.add(service);
+			if (service != null) {
+				this.services.add(service);
+			}
 			return this;
 		}
 
 		public DeployApplicationRequestBuilder services(List<String> services) {
-			this.services.addAll(services);
+			if (!CollectionUtils.isEmpty(services)) {
+				this.services.addAll(services);
+			}
 			return this;
 		}
 
diff --git a/spring-cloud-app-broker-deployer/src/main/java/org/springframework/cloud/appbroker/deployer/UndeployApplicationRequest.java b/spring-cloud-app-broker-deployer/src/main/java/org/springframework/cloud/appbroker/deployer/UndeployApplicationRequest.java
index e63b7b0..9e4b8ba 100644
--- a/spring-cloud-app-broker-deployer/src/main/java/org/springframework/cloud/appbroker/deployer/UndeployApplicationRequest.java
+++ b/spring-cloud-app-broker-deployer/src/main/java/org/springframework/cloud/appbroker/deployer/UndeployApplicationRequest.java
@@ -16,8 +16,11 @@
 
 package org.springframework.cloud.appbroker.deployer;
 
+import java.util.HashMap;
 import java.util.Map;
 
+import org.springframework.util.CollectionUtils;
+
 public class UndeployApplicationRequest {
 
 	private final String name;
@@ -43,7 +46,7 @@ public class UndeployApplicationRequest {
 	public static class UndeployApplicationRequestBuilder {
 
 		private String name;
-		private Map<String, String> properties;
+		private final Map<String, String> properties = new HashMap<>();
 
 		UndeployApplicationRequestBuilder() {
 		}
@@ -54,7 +57,9 @@ public class UndeployApplicationRequest {
 		}
 
 		public UndeployApplicationRequestBuilder properties(Map<String, String> properties) {
-			this.properties = properties;
+			if (!CollectionUtils.isEmpty(properties)) {
+				this.properties.putAll(properties);
+			}
 			return this;
 		}
 
diff --git a/spring-cloud-app-broker-deployer/src/main/java/org/springframework/cloud/appbroker/deployer/UpdateApplicationRequest.java b/spring-cloud-app-broker-deployer/src/main/java/org/springframework/cloud/appbroker/deployer/UpdateApplicationRequest.java
index bed37b4..529ffc3 100644
--- a/spring-cloud-app-broker-deployer/src/main/java/org/springframework/cloud/appbroker/deployer/UpdateApplicationRequest.java
+++ b/spring-cloud-app-broker-deployer/src/main/java/org/springframework/cloud/appbroker/deployer/UpdateApplicationRequest.java
@@ -21,6 +21,8 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
+import org.springframework.util.CollectionUtils;
+
 public class UpdateApplicationRequest {
 
 	private final String name;
@@ -97,38 +99,44 @@ public class UpdateApplicationRequest {
 		}
 
 		public UpdateApplicationRequestBuilder property(String key, String value) {
-			this.properties.put(key, value);
+			if (key != null && value != null) {
+				this.properties.put(key, value);
+			}
 			return this;
 		}
 
 		public UpdateApplicationRequestBuilder properties(Map<String, String> properties) {
-			if (properties == null) {
-				return this;
+			if (!CollectionUtils.isEmpty(properties)) {
+				this.properties.putAll(properties);
 			}
-			this.properties.putAll(properties);
 			return this;
 		}
 
 		public UpdateApplicationRequestBuilder environment(String key, String value) {
-			this.environment.put(key, value);
+			if (key != null && value != null) {
+				this.environment.put(key, value);
+			}
 			return this;
 		}
 
 		public UpdateApplicationRequestBuilder environment(Map<String, Object> environment) {
-			if (environment == null) {
-				return this;
+			if (!CollectionUtils.isEmpty(environment)) {
+				this.environment.putAll(environment);
 			}
-			this.environment.putAll(environment);
 			return this;
 		}
 
 		public UpdateApplicationRequestBuilder service(String service) {
-			this.services.add(service);
+			if (service != null) {
+				this.services.add(service);
+			}
 			return this;
 		}
 
 		public UpdateApplicationRequestBuilder services(List<String> services) {
-			this.services.addAll(services);
+			if (!CollectionUtils.isEmpty(services)) {
+				this.services.addAll(services);
+			}
 			return this;
 		}
 
diff --git a/spring-cloud-app-broker-deployer/src/main/java/org/springframework/cloud/appbroker/deployer/UpdateServiceInstanceRequest.java b/spring-cloud-app-broker-deployer/src/main/java/org/springframework/cloud/appbroker/deployer/UpdateServiceInstanceRequest.java
index 696f447..c9a7fe5 100644
--- a/spring-cloud-app-broker-deployer/src/main/java/org/springframework/cloud/appbroker/deployer/UpdateServiceInstanceRequest.java
+++ b/spring-cloud-app-broker-deployer/src/main/java/org/springframework/cloud/appbroker/deployer/UpdateServiceInstanceRequest.java
@@ -19,6 +19,8 @@ package org.springframework.cloud.appbroker.deployer;
 import java.util.HashMap;
 import java.util.Map;
 
+import org.springframework.util.CollectionUtils;
+
 public class UpdateServiceInstanceRequest {
 
 	private final String serviceInstanceName;
@@ -72,23 +74,23 @@ public class UpdateServiceInstanceRequest {
 		}
 
 		public UpdateServiceInstanceRequestBuilder parameters(String key, String value) {
-			this.parameters.put(key, value);
+			if (key != null && value != null) {
+				this.parameters.put(key, value);
+			}
 			return this;
 		}
 
 		public UpdateServiceInstanceRequestBuilder parameters(Map<String, Object> parameters) {
-			if (parameters == null) {
-				return this;
+			if (!CollectionUtils.isEmpty(parameters)) {
+				this.parameters.putAll(parameters);
 			}
-			this.parameters.putAll(parameters);
 			return this;
 		}
 
 		public UpdateServiceInstanceRequestBuilder properties(Map<String, String> properties) {
-			if (properties == null) {
-				return this;
+			if (!CollectionUtils.isEmpty(properties)) {
+				this.properties.putAll(properties);
 			}
-			this.properties.putAll(properties);
 			return this;
 		}
 
diff --git a/spring-cloud-app-broker-deployer/src/main/java/org/springframework/cloud/appbroker/oauth2/CreateOAuth2ClientRequest.java b/spring-cloud-app-broker-deployer/src/main/java/org/springframework/cloud/appbroker/oauth2/CreateOAuth2ClientRequest.java
index 5029421..d6bc8e7 100644
--- a/spring-cloud-app-broker-deployer/src/main/java/org/springframework/cloud/appbroker/oauth2/CreateOAuth2ClientRequest.java
+++ b/spring-cloud-app-broker-deployer/src/main/java/org/springframework/cloud/appbroker/oauth2/CreateOAuth2ClientRequest.java
@@ -16,6 +16,7 @@
 
 package org.springframework.cloud.appbroker.oauth2;
 
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 import java.util.Objects;
@@ -124,9 +125,9 @@ public class CreateOAuth2ClientRequest {
 		private String clientId;
 		private String clientSecret;
 		private String clientName;
-		private List<String> scopes;
-		private List<String> authorities;
-		private List<String> grantTypes;
+		private final List<String> scopes = new ArrayList<>();
+		private final List<String> authorities = new ArrayList<>();
+		private final List<String> grantTypes = new ArrayList<>();
 		private String identityZoneSubdomain;
 		private String identityZoneId;
 
@@ -149,17 +150,23 @@ public class CreateOAuth2ClientRequest {
 		}
 
 		public CreateOAuth2ClientRequestBuilder scopes(String... scopes) {
-			this.scopes = Arrays.asList(scopes);
+			if (scopes != null) {
+				this.scopes.addAll(Arrays.asList(scopes));
+			}
 			return this;
 		}
 
 		public CreateOAuth2ClientRequestBuilder authorities(String... authorities) {
-			this.authorities = Arrays.asList(authorities);
+			if (authorities != null) {
+				this.authorities.addAll(Arrays.asList(authorities));
+			}
 			return this;
 		}
 
 		public CreateOAuth2ClientRequestBuilder grantTypes(String... grantTypes) {
-			this.grantTypes = Arrays.asList(grantTypes);
+			if (grantTypes != null) {
+				this.grantTypes.addAll(Arrays.asList(grantTypes));
+			}
 			return this;
 		}
 
diff --git a/spring-cloud-app-broker-deployer/src/main/java/org/springframework/cloud/appbroker/oauth2/CreateOAuth2ClientResponse.java b/spring-cloud-app-broker-deployer/src/main/java/org/springframework/cloud/appbroker/oauth2/CreateOAuth2ClientResponse.java
index df84586..6ac1ffe 100644
--- a/spring-cloud-app-broker-deployer/src/main/java/org/springframework/cloud/appbroker/oauth2/CreateOAuth2ClientResponse.java
+++ b/spring-cloud-app-broker-deployer/src/main/java/org/springframework/cloud/appbroker/oauth2/CreateOAuth2ClientResponse.java
@@ -16,9 +16,12 @@
 
 package org.springframework.cloud.appbroker.oauth2;
 
+import java.util.ArrayList;
 import java.util.List;
 import java.util.Objects;
 
+import org.springframework.util.CollectionUtils;
+
 public class CreateOAuth2ClientResponse {
 
 	private final String clientId;
@@ -97,9 +100,9 @@ public class CreateOAuth2ClientResponse {
 	public static class CreateOAuth2ClientResponseBuilder {
 		private String clientId;
 		private String clientName;
-		private List<String> scopes;
-		private List<String> authorities;
-		private List<String> grantTypes;
+		private final List<String> scopes = new ArrayList<>();
+		private final List<String> authorities = new ArrayList<>();
+		private final List<String> grantTypes = new ArrayList<>();
 
 		CreateOAuth2ClientResponseBuilder() {
 		}
@@ -115,17 +118,23 @@ public class CreateOAuth2ClientResponse {
 		}
 
 		public CreateOAuth2ClientResponseBuilder scopes(List<String> scopes) {
-			this.scopes = scopes;
+			if (scopes != null) {
+				this.scopes.addAll(scopes);
+			}
 			return this;
 		}
 
 		public CreateOAuth2ClientResponseBuilder authorities(List<String> authorities) {
-			this.authorities = authorities;
+			if (!CollectionUtils.isEmpty(authorities)) {
+				this.authorities.addAll(authorities);
+			}
 			return this;
 		}
 
 		public CreateOAuth2ClientResponseBuilder grantTypes(List<String> grantTypes) {
-			this.grantTypes = grantTypes;
+			if (!CollectionUtils.isEmpty(grantTypes)) {
+				this.grantTypes.addAll(grantTypes);
+			}
 			return this;
 		}
 
diff --git a/spring-cloud-app-broker-deployer/src/main/java/org/springframework/cloud/appbroker/oauth2/DeleteOAuth2ClientResponse.java b/spring-cloud-app-broker-deployer/src/main/java/org/springframework/cloud/appbroker/oauth2/DeleteOAuth2ClientResponse.java
index 869a512..7514bf3 100644
--- a/spring-cloud-app-broker-deployer/src/main/java/org/springframework/cloud/appbroker/oauth2/DeleteOAuth2ClientResponse.java
+++ b/spring-cloud-app-broker-deployer/src/main/java/org/springframework/cloud/appbroker/oauth2/DeleteOAuth2ClientResponse.java
@@ -16,9 +16,12 @@
 
 package org.springframework.cloud.appbroker.oauth2;
 
+import java.util.ArrayList;
 import java.util.List;
 import java.util.Objects;
 
+import org.springframework.util.CollectionUtils;
+
 public class DeleteOAuth2ClientResponse {
 	private final String clientId;
 	private final String clientName;
@@ -95,9 +98,9 @@ public class DeleteOAuth2ClientResponse {
 	public static class DeleteOAuth2ClientResponseBuilder {
 		private String clientId;
 		private String clientName;
-		private List<String> scopes;
-		private List<String> authorities;
-		private List<String> grantTypes;
+		private final List<String> scopes = new ArrayList<>();
+		private final List<String> authorities = new ArrayList<>();
+		private final List<String> grantTypes = new ArrayList<>();
 
 		DeleteOAuth2ClientResponseBuilder() {
 		}
@@ -113,17 +116,23 @@ public class DeleteOAuth2ClientResponse {
 		}
 
 		public DeleteOAuth2ClientResponseBuilder scopes(List<String> scopes) {
-			this.scopes = scopes;
+			if (!CollectionUtils.isEmpty(scopes)) {
+				this.scopes.addAll(scopes);
+			}
 			return this;
 		}
 
 		public DeleteOAuth2ClientResponseBuilder authorities(List<String> authorities) {
-			this.authorities = authorities;
+			if (!CollectionUtils.isEmpty(authorities)) {
+				this.authorities.addAll(authorities);
+			}
 			return this;
 		}
 
 		public DeleteOAuth2ClientResponseBuilder grantTypes(List<String> grantTypes) {
-			this.grantTypes = grantTypes;
+			if (!CollectionUtils.isEmpty(grantTypes)) {
+				this.grantTypes.addAll(grantTypes);
+			}
 			return this;
 		}