Reduce implementation dependencies

CedarJava/build.gradle

@@ -60,18 +60,19 @@ repositories {
     mavenCentral()
 }
 
+configurations {
+    testCompileOnly.extendsFrom compileOnly
+}
+
 dependencies {
     // Do not upgrade to Jackson 3.x without addressing stack overflow issues in ValueCedarDeserializer
     // The upgrade should be reviewed by AppSec
     implementation 'com.fasterxml.jackson.core:jackson-databind:2.15.0'
     implementation 'com.fasterxml.jackson.datatype:jackson-datatype-jdk8:2.15.0'
     implementation 'org.slf4j:slf4j-api:2.0.7'
-    implementation 'org.apache.commons:commons-text:1.10.0'
-    implementation 'com.google.code.findbugs:findbugs:3.0.1'
-    implementation 'org.apache.logging.log4j:log4j-core:2.20.0'
-    implementation 'org.apache.logging.log4j:log4j-to-slf4j:2.20.0'
-    implementation 'com.google.guava:guava:31.0.1-jre'
-
+    compileOnly 'com.google.code.findbugs:findbugs:3.0.1'
+    testImplementation 'org.apache.logging.log4j:log4j-core:2.20.0'
+    testImplementation 'org.apache.logging.log4j:log4j-to-slf4j:2.20.0'
     testImplementation 'org.junit.jupiter:junit-jupiter-params:5.9.3'
     testImplementation 'org.junit.jupiter:junit-jupiter-engine:5.9.3'
     testImplementation 'org.mockito:mockito-inline:5.2.0'

CedarJava/src/main/java/com/cedarpolicy/model/AuthorizationResponse.java

@@ -19,10 +19,9 @@
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonProperty;
 import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
+import java.util.Collections;
 import java.util.List;
 import java.util.Set;
-import com.google.common.collect.ImmutableList;
-import com.google.common.collect.ImmutableSet;
 
 /**
  * The result of processing an AuthorizationRequest. The answer to the request is contained in the
@@ -54,10 +53,10 @@ public static class Diagnostics {
          * Set of policyID's that caused the decision. For example, when a policy evaluates to Deny,
          * all deny policies that evaluated to True will appear in Reasons.
          */
-        private ImmutableSet<String> reason;
+        private Set<String> reason;
 
         /** Set of errors and warnings returned by Cedar. */
-        private ImmutableList<String> errors;
+        private List<String> errors;
 
         /**
          * Read the reasons and errors from a JSON object.
@@ -69,8 +68,8 @@ public static class Diagnostics {
         public Diagnostics(
                 @JsonProperty("reason") Set<String> reason,
                 @JsonProperty("errors") List<String> errors) {
-            this.errors = ImmutableList.copyOf(errors);
-            this.reason = ImmutableSet.copyOf(reason);
+            this.errors = Collections.unmodifiableList(errors);
+            this.reason = Collections.unmodifiableSet(reason);
         }
     }
 
@@ -137,7 +136,7 @@ public Set<String> getReasons() {
      *
      * @return list with errors that happened for a given Request
      */
-    public java.util.List<String> getErrors() {
+    public List<String> getErrors() {
         return diagnostics.errors;
     }
 

CedarJava/src/main/java/com/cedarpolicy/model/slice/TemplateInstantiation.java

@@ -18,8 +18,8 @@
 
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonProperty;
+import java.util.Collections;
 import java.util.List;
-import com.google.common.collect.ImmutableList;
 
 /** Template instantiation. */
 public class TemplateInstantiation {
@@ -46,7 +46,7 @@ public TemplateInstantiation(
             @JsonProperty("instantiations") List<Instantiation> instantiations) {
         this.templateId = templateId;
         this.resultPolicyId = resultPolicyId;
-        this.instantiations = ImmutableList.copyOf(instantiations);
+        this.instantiations = Collections.unmodifiableList(instantiations);
     }
 
     /** Get the template ID. */