diff --git a/spring-vault-core/src/main/java/org/springframework/vault/annotation/package-info.java b/spring-vault-core/src/main/java/org/springframework/vault/annotation/package-info.java
index ddace64e..99c839c8 100644
--- a/spring-vault-core/src/main/java/org/springframework/vault/annotation/package-info.java
+++ b/spring-vault-core/src/main/java/org/springframework/vault/annotation/package-info.java
@@ -1,8 +1,7 @@
 /**
  * Annotation support for the Spring Vault.
  */
-@NonNullApi
+@org.springframework.lang.NonNullApi
+@org.springframework.lang.NonNullFields
 package org.springframework.vault.annotation;
 
-import org.springframework.lang.NonNullApi;
-
diff --git a/spring-vault-core/src/main/java/org/springframework/vault/authentication/package-info.java b/spring-vault-core/src/main/java/org/springframework/vault/authentication/package-info.java
index 09894b5d..c44b841b 100644
--- a/spring-vault-core/src/main/java/org/springframework/vault/authentication/package-info.java
+++ b/spring-vault-core/src/main/java/org/springframework/vault/authentication/package-info.java
@@ -1,7 +1,6 @@
 /**
  * Support for authentication and session management.
  */
-@NonNullApi
+@org.springframework.lang.NonNullApi
+@org.springframework.lang.NonNullFields
 package org.springframework.vault.authentication;
-
-import org.springframework.lang.NonNullApi;
diff --git a/spring-vault-core/src/main/java/org/springframework/vault/client/package-info.java b/spring-vault-core/src/main/java/org/springframework/vault/client/package-info.java
index a028b4ca..5c9ec697 100644
--- a/spring-vault-core/src/main/java/org/springframework/vault/client/package-info.java
+++ b/spring-vault-core/src/main/java/org/springframework/vault/client/package-info.java
@@ -1,7 +1,6 @@
 /**
  * Spring Vault Client abstraction.
  */
-@NonNullApi
+@org.springframework.lang.NonNullApi
+@org.springframework.lang.NonNullFields
 package org.springframework.vault.client;
-
-import org.springframework.lang.NonNullApi;
diff --git a/spring-vault-core/src/main/java/org/springframework/vault/config/AbstractVaultConfiguration.java b/spring-vault-core/src/main/java/org/springframework/vault/config/AbstractVaultConfiguration.java
index 0eb27aea..5a241242 100644
--- a/spring-vault-core/src/main/java/org/springframework/vault/config/AbstractVaultConfiguration.java
+++ b/spring-vault-core/src/main/java/org/springframework/vault/config/AbstractVaultConfiguration.java
@@ -24,6 +24,7 @@ import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.core.env.Environment;
 import org.springframework.http.client.ClientHttpRequestFactory;
+import org.springframework.lang.Nullable;
 import org.springframework.scheduling.concurrent.ThreadPoolTaskScheduler;
 import org.springframework.util.Assert;
 import org.springframework.vault.authentication.ClientAuthentication;
@@ -48,7 +49,7 @@ import org.springframework.web.client.RestOperations;
 @Configuration
 public abstract class AbstractVaultConfiguration implements ApplicationContextAware {
 
-	private ApplicationContext applicationContext;
+	private @Nullable ApplicationContext applicationContext;
 
 	/**
 	 * @return Vault endpoint coordinates for HTTP/HTTPS communication, must not be
diff --git a/spring-vault-core/src/main/java/org/springframework/vault/config/EnvironmentVaultConfiguration.java b/spring-vault-core/src/main/java/org/springframework/vault/config/EnvironmentVaultConfiguration.java
index c976273c..6f475c34 100644
--- a/spring-vault-core/src/main/java/org/springframework/vault/config/EnvironmentVaultConfiguration.java
+++ b/spring-vault-core/src/main/java/org/springframework/vault/config/EnvironmentVaultConfiguration.java
@@ -22,6 +22,7 @@ import org.springframework.context.ApplicationContext;
 import org.springframework.context.ApplicationContextAware;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.core.io.Resource;
+import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
 import org.springframework.util.StringUtils;
 import org.springframework.vault.authentication.AppIdAuthentication;
@@ -137,8 +138,8 @@ import org.springframework.web.client.RestOperations;
 public class EnvironmentVaultConfiguration extends AbstractVaultConfiguration implements
 		ApplicationContextAware {
 
-	private RestOperations cachedRestOperations;
-	private ApplicationContext applicationContext;
+	private @Nullable RestOperations cachedRestOperations;
+	private @Nullable ApplicationContext applicationContext;
 
 	@Override
 	public RestOperations restOperations() {
@@ -324,10 +325,12 @@ public class EnvironmentVaultConfiguration extends AbstractVaultConfiguration im
 		return new CubbyholeAuthentication(options, restOperations());
 	}
 
+	@Nullable
 	private String getProperty(String key) {
 		return getEnvironment().getProperty(key);
 	}
 
+	@Nullable
 	private Resource getResource(String key) {
 
 		String value = getProperty(key);
diff --git a/spring-vault-core/src/main/java/org/springframework/vault/config/package-info.java b/spring-vault-core/src/main/java/org/springframework/vault/config/package-info.java
index 3bdbffc1..fd296b5a 100644
--- a/spring-vault-core/src/main/java/org/springframework/vault/config/package-info.java
+++ b/spring-vault-core/src/main/java/org/springframework/vault/config/package-info.java
@@ -1,5 +1,7 @@
 /**
  * Spring configuration for Vault.
  */
+@org.springframework.lang.NonNullApi
+@org.springframework.lang.NonNullFields
 package org.springframework.vault.config;
 
diff --git a/spring-vault-core/src/main/java/org/springframework/vault/core/env/package-info.java b/spring-vault-core/src/main/java/org/springframework/vault/core/env/package-info.java
index c52702ad..49ff7a84 100644
--- a/spring-vault-core/src/main/java/org/springframework/vault/core/env/package-info.java
+++ b/spring-vault-core/src/main/java/org/springframework/vault/core/env/package-info.java
@@ -1,7 +1,6 @@
 /**
  * Spring Vault's environment abstraction consisting property source support.
  */
-@NonNullApi
+@org.springframework.lang.NonNullApi
+@org.springframework.lang.NonNullFields
 package org.springframework.vault.core.env;
-
-import org.springframework.lang.NonNullApi;
diff --git a/spring-vault-core/src/main/java/org/springframework/vault/core/lease/domain/package-info.java b/spring-vault-core/src/main/java/org/springframework/vault/core/lease/domain/package-info.java
index da6289cf..ec9c4db5 100644
--- a/spring-vault-core/src/main/java/org/springframework/vault/core/lease/domain/package-info.java
+++ b/spring-vault-core/src/main/java/org/springframework/vault/core/lease/domain/package-info.java
@@ -1,7 +1,6 @@
 /**
  * Lease domain classes.
  */
-@NonNullApi
+@org.springframework.lang.NonNullApi
+@org.springframework.lang.NonNullFields
 package org.springframework.vault.core.lease.domain;
-
-import org.springframework.lang.NonNullApi;
diff --git a/spring-vault-core/src/main/java/org/springframework/vault/core/lease/event/package-info.java b/spring-vault-core/src/main/java/org/springframework/vault/core/lease/event/package-info.java
index 81a9e702..43cf4acb 100644
--- a/spring-vault-core/src/main/java/org/springframework/vault/core/lease/event/package-info.java
+++ b/spring-vault-core/src/main/java/org/springframework/vault/core/lease/event/package-info.java
@@ -1,7 +1,6 @@
 /**
  * Support classes for lease application events.
  */
-@NonNullApi
+@org.springframework.lang.NonNullApi
+@org.springframework.lang.NonNullFields
 package org.springframework.vault.core.lease.event;
-
-import org.springframework.lang.NonNullApi;
diff --git a/spring-vault-core/src/main/java/org/springframework/vault/core/lease/package-info.java b/spring-vault-core/src/main/java/org/springframework/vault/core/lease/package-info.java
index 202799d9..986da0f8 100644
--- a/spring-vault-core/src/main/java/org/springframework/vault/core/lease/package-info.java
+++ b/spring-vault-core/src/main/java/org/springframework/vault/core/lease/package-info.java
@@ -1,7 +1,6 @@
 /**
  * The core package implementing lease renewal and secret rotation.
  */
-@NonNullApi
+@org.springframework.lang.NonNullApi
+@org.springframework.lang.NonNullFields
 package org.springframework.vault.core.lease;
-
-import org.springframework.lang.NonNullApi;
diff --git a/spring-vault-core/src/main/java/org/springframework/vault/core/package-info.java b/spring-vault-core/src/main/java/org/springframework/vault/core/package-info.java
index 9f734b65..2db7821d 100644
--- a/spring-vault-core/src/main/java/org/springframework/vault/core/package-info.java
+++ b/spring-vault-core/src/main/java/org/springframework/vault/core/package-info.java
@@ -1,7 +1,6 @@
 /**
  * Vault core support.
  */
-@NonNullApi
+@org.springframework.lang.NonNullApi
+@org.springframework.lang.NonNullFields
 package org.springframework.vault.core;
-
-import org.springframework.lang.NonNullApi;
diff --git a/spring-vault-core/src/main/java/org/springframework/vault/core/util/package-info.java b/spring-vault-core/src/main/java/org/springframework/vault/core/util/package-info.java
index 6474ef71..ab4f1dc6 100644
--- a/spring-vault-core/src/main/java/org/springframework/vault/core/util/package-info.java
+++ b/spring-vault-core/src/main/java/org/springframework/vault/core/util/package-info.java
@@ -1,8 +1,7 @@
 /**
  * Property transformer classes for Spring Vault core support.
  */
-@NonNullApi
+@org.springframework.lang.NonNullApi
+@org.springframework.lang.NonNullFields
 package org.springframework.vault.core.util;
 
-import org.springframework.lang.NonNullApi;
-
diff --git a/spring-vault-core/src/main/java/org/springframework/vault/package-info.java b/spring-vault-core/src/main/java/org/springframework/vault/package-info.java
index 4a73c3c3..3fad8f92 100644
--- a/spring-vault-core/src/main/java/org/springframework/vault/package-info.java
+++ b/spring-vault-core/src/main/java/org/springframework/vault/package-info.java
@@ -1,7 +1,6 @@
 /**
  * Spring support for <a href="https://vaultproject.io">Hashicorp Vault</a>.
  */
-@NonNullApi
+@org.springframework.lang.NonNullApi
+@org.springframework.lang.NonNullFields
 package org.springframework.vault;
-
-import org.springframework.lang.NonNullApi;
diff --git a/spring-vault-core/src/main/java/org/springframework/vault/support/package-info.java b/spring-vault-core/src/main/java/org/springframework/vault/support/package-info.java
index 21dcc895..f91b26be 100644
--- a/spring-vault-core/src/main/java/org/springframework/vault/support/package-info.java
+++ b/spring-vault-core/src/main/java/org/springframework/vault/support/package-info.java
@@ -1,8 +1,7 @@
 /**
  * Classes supporting the Vault packages, such as value objects.
  */
-@NonNullApi
+@org.springframework.lang.NonNullApi
+@org.springframework.lang.NonNullFields
 package org.springframework.vault.support;
 
-import org.springframework.lang.NonNullApi;
-