fix(policies): handle null policies list in listDynamicPolicies (#40)

* fix(policies): handle null policies list in listDynamicPolicies

When the API returns {"policies": null} instead of {"policies": []},
the SDK now correctly returns an empty list instead of throwing NPE.

Fixes getaxonflow/axonflow-enterprise#40

* chore: bump version to 2.1.1 for patch release

- Added changelog entry for null policies list fix
- Updated pom.xml version from 2.1.0 to 2.1.1

* fix: handle null policies list in all policy methods

- Add null checks for wrapper and list fields in:
  - listDynamicPolicies()
  - getEffectiveDynamicPolicies()
  - listStaticPolicies()
  - getEffectiveStaticPolicies()
- Return empty list when wrapper or list is null
- Add unit tests for null handling in all 4 methods
- Bump version to 2.1.1

Fixes #40

Author: saurabhjain1592

CHANGELOG.md

@@ -5,6 +5,15 @@ All notable changes to the AxonFlow Java SDK will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [2.1.1] - 2026-01-06
+
+### Fixed
+
+- **Null Policies List Handling**: Fixed `NullPointerException` in list-returning policy methods when API returns null instead of empty array
+  - Affected methods: `listDynamicPolicies()`, `getEffectiveDynamicPolicies()`, `listStaticPolicies()`, `getEffectiveStaticPolicies()`
+  - Added explicit null check for wrapper and list fields before returning
+  - Returns empty list when wrapper or list field is null
+
 ## [2.1.0] - 2026-01-05
 
 ### Added

pom.xml

@@ -6,7 +6,7 @@
 
     <groupId>com.getaxonflow</groupId>
     <artifactId>axonflow-sdk</artifactId>
-    <version>2.1.0</version>
+    <version>2.1.1</version>
     <packaging>jar</packaging>
 
     <name>AxonFlow Java SDK</name>

src/main/java/com/getaxonflow/sdk/AxonFlow.java

@@ -906,7 +906,11 @@ public List<StaticPolicy> listStaticPolicies(ListStaticPoliciesOptions options)
             Request httpRequest = buildRequest("GET", path, null);
             try (Response response = httpClient.newCall(httpRequest).execute()) {
                 StaticPoliciesResponse wrapper = parseResponse(response, StaticPoliciesResponse.class);
-                return wrapper.getPolicies() != null ? wrapper.getPolicies() : java.util.Collections.emptyList();
+                // Handle null wrapper or null policies list (Issue #40)
+                if (wrapper == null || wrapper.getPolicies() == null) {
+                    return java.util.Collections.emptyList();
+                }
+                return wrapper.getPolicies();
             }
         }, "listStaticPolicies");
     }
@@ -1081,7 +1085,11 @@ public List<StaticPolicy> getEffectiveStaticPolicies(EffectivePoliciesOptions op
             Request httpRequest = buildRequest("GET", path.toString(), null);
             try (Response response = httpClient.newCall(httpRequest).execute()) {
                 EffectivePoliciesResponse wrapper = parseResponse(response, EffectivePoliciesResponse.class);
-                return wrapper.getStaticPolicies() != null ? wrapper.getStaticPolicies() : java.util.Collections.emptyList();
+                // Handle null wrapper or null policies list (Issue #40)
+                if (wrapper == null || wrapper.getStaticPolicies() == null) {
+                    return java.util.Collections.emptyList();
+                }
+                return wrapper.getStaticPolicies();
             }
         }, "getEffectiveStaticPolicies");
     }
@@ -1228,7 +1236,11 @@ public List<DynamicPolicy> listDynamicPolicies(ListDynamicPoliciesOptions option
             try (Response response = httpClient.newCall(httpRequest).execute()) {
                 // Agent proxy (Issue #886) returns {"policies": [...]} wrapper
                 DynamicPoliciesResponse wrapper = parseResponse(response, DynamicPoliciesResponse.class);
-                return wrapper != null ? wrapper.getPolicies() : java.util.Collections.emptyList();
+                // Handle null wrapper or null policies list (Issue #40)
+                if (wrapper == null || wrapper.getPolicies() == null) {
+                    return java.util.Collections.emptyList();
+                }
+                return wrapper.getPolicies();
             }
         }, "listDynamicPolicies");
     }
@@ -1360,7 +1372,11 @@ public List<DynamicPolicy> getEffectiveDynamicPolicies(EffectivePoliciesOptions
             try (Response response = httpClient.newCall(httpRequest).execute()) {
                 // Agent proxy (Issue #886) returns {"policies": [...]} wrapper
                 DynamicPoliciesResponse wrapper = parseResponse(response, DynamicPoliciesResponse.class);
-                return wrapper != null ? wrapper.getPolicies() : java.util.Collections.emptyList();
+                // Handle null wrapper or null policies list (Issue #40)
+                if (wrapper == null || wrapper.getPolicies() == null) {
+                    return java.util.Collections.emptyList();
+                }
+                return wrapper.getPolicies();
             }
         }, "getEffectiveDynamicPolicies");
     }

src/test/java/com/getaxonflow/sdk/PolicyTest.java

@@ -111,6 +111,20 @@ void listStaticPoliciesShouldReturnPolicies() {
             assertThat(policies.get(0).getName()).isEqualTo("Block SQL Injection");
         }
 
+        @Test
+        @DisplayName("listStaticPolicies should return empty list when policies is null")
+        void listStaticPoliciesShouldReturnEmptyListWhenNull() {
+            stubFor(get(urlPathEqualTo("/api/v1/static-policies"))
+                .willReturn(aResponse()
+                    .withStatus(200)
+                    .withHeader("Content-Type", "application/json")
+                    .withBody("{\"policies\": null}")));
+
+            List<StaticPolicy> policies = axonflow.listStaticPolicies();
+
+            assertThat(policies).isEmpty();
+        }
+
         @Test
         @DisplayName("listStaticPolicies with filters should include query params")
         void listStaticPoliciesWithFiltersShouldIncludeQueryParams() {
@@ -259,6 +273,21 @@ void getEffectiveStaticPoliciesShouldReturnEffectivePolicies() {
             assertThat(policies).hasSize(1);
         }
 
+        @Test
+        @DisplayName("getEffectiveStaticPolicies should return empty list when static is null")
+        void getEffectiveStaticPoliciesShouldReturnEmptyListWhenNull() {
+            // Issue #40: Handle null policies list
+            stubFor(get(urlPathEqualTo("/api/v1/static-policies/effective"))
+                .willReturn(aResponse()
+                    .withStatus(200)
+                    .withHeader("Content-Type", "application/json")
+                    .withBody("{\"static\": null, \"dynamic\": []}")));
+
+            List<StaticPolicy> policies = axonflow.getEffectiveStaticPolicies();
+
+            assertThat(policies).isEmpty();
+        }
+
         @Test
         @DisplayName("testPattern should test pattern against inputs")
         void testPatternShouldTestPatternAgainstInputs() {
@@ -411,6 +440,21 @@ void listDynamicPoliciesShouldReturnPolicies() {
             assertThat(policies.get(0).getName()).isEqualTo("Rate Limit API");
         }
 
+        @Test
+        @DisplayName("listDynamicPolicies should return empty list when policies is null")
+        void listDynamicPoliciesShouldReturnEmptyListWhenNull() {
+            // Issue #40: Handle null policies list
+            stubFor(get(urlPathEqualTo("/api/v1/dynamic-policies"))
+                .willReturn(aResponse()
+                    .withStatus(200)
+                    .withHeader("Content-Type", "application/json")
+                    .withBody("{\"policies\": null}")));
+
+            List<DynamicPolicy> policies = axonflow.listDynamicPolicies();
+
+            assertThat(policies).isEmpty();
+        }
+
         @Test
         @DisplayName("listDynamicPolicies with filters should include query params")
         void listDynamicPoliciesWithFiltersShouldIncludeQueryParams() {
@@ -563,6 +607,21 @@ void getEffectiveDynamicPoliciesShouldReturnEffectivePolicies() {
 
             assertThat(policies).hasSize(1);
         }
+
+        @Test
+        @DisplayName("getEffectiveDynamicPolicies should return empty list when policies is null")
+        void getEffectiveDynamicPoliciesShouldReturnEmptyListWhenNull() {
+            // Issue #40: Handle null policies list
+            stubFor(get(urlPathEqualTo("/api/v1/dynamic-policies/effective"))
+                .willReturn(aResponse()
+                    .withStatus(200)
+                    .withHeader("Content-Type", "application/json")
+                    .withBody("{\"policies\": null}")));
+
+            List<DynamicPolicy> policies = axonflow.getEffectiveDynamicPolicies();
+
+            assertThat(policies).isEmpty();
+        }
     }
 
     // ========================================================================