diff --git a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/context/CanonicalResourceManager.java b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/context/CanonicalResourceManager.java
index f9fe41938..980e22ea1 100644
--- a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/context/CanonicalResourceManager.java
+++ b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/context/CanonicalResourceManager.java
@@ -195,8 +195,13 @@ public class CanonicalResourceManager<T extends CanonicalResource> {
       } else {
         return resource instanceof StructureDefinition ? ((StructureDefinition) resource).getDerivationElement().primitiveValue() : null;
       }
-    }  
+    }
 
+    public void unload() {
+      if (proxy != null) {
+        resource = null;
+      }      
+    }  
   }
 
   public class MetadataResourceVersionComparator<T1 extends CachedCanonicalResource<T>> implements Comparator<T1> {
@@ -659,4 +664,12 @@ public class CanonicalResourceManager<T extends CanonicalResource> {
   }
 
 
+  public void unload() {
+    for (CachedCanonicalResource<T> t : list) {
+      t.unload();
+    }
+   
+  }
+
+
 }
\ No newline at end of file
diff --git a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/context/TypeManager.java b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/context/TypeManager.java
index 8450989cd..ed1909ea9 100644
--- a/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/context/TypeManager.java
+++ b/org.hl7.fhir.r5/src/main/java/org/hl7/fhir/r5/context/TypeManager.java
@@ -126,5 +126,14 @@ public class TypeManager {
       return sd != null && sd.getKind() == StructureDefinitionKind.COMPLEXTYPE;      
     }
   }
+
+  public void unload() {
+
+    structures.unload();
+    typeDefinitions.clear(); 
+    fhirTypeDefinitions.clear();
+    primitiveNames.clear();
+    dataTypeNames.clear();
+  }
   
 }
diff --git a/org.hl7.fhir.validation/src/main/java/org/hl7/fhir/validation/ValidationEngine.java b/org.hl7.fhir.validation/src/main/java/org/hl7/fhir/validation/ValidationEngine.java
index cd7cf08f9..b7de224ae 100644
--- a/org.hl7.fhir.validation/src/main/java/org/hl7/fhir/validation/ValidationEngine.java
+++ b/org.hl7.fhir.validation/src/main/java/org/hl7/fhir/validation/ValidationEngine.java
@@ -28,6 +28,7 @@ import org.hl7.fhir.exceptions.DefinitionException;
 import org.hl7.fhir.exceptions.FHIRException;
 import org.hl7.fhir.r5.conformance.profile.ProfileUtilities;
 import org.hl7.fhir.r5.context.ContextUtilities;
+import org.hl7.fhir.r5.context.ILoggingService;
 import org.hl7.fhir.r5.context.IWorkerContext;
 import org.hl7.fhir.r5.context.IWorkerContextManager;
 import org.hl7.fhir.r5.context.SimpleWorkerContext;
@@ -324,7 +325,7 @@ public class ValidationEngine implements IValidatorResourceFetcher, IValidationP
     private final boolean canRunWithoutTerminologyServer;
 
     @With
-    private final IWorkerContext.ILoggingService loggingService;
+    private final ILoggingService loggingService;
 
     @With
     private boolean THO = true;
@@ -342,7 +343,7 @@ public class ValidationEngine implements IValidatorResourceFetcher, IValidationP
       loggingService = new SystemOutLoggingService();
     }
 
-    public ValidationEngineBuilder(String terminologyCachePath, String userAgent, String version, String txServer, String txLog, FhirPublication txVersion, TimeTracker timeTracker, boolean canRunWithoutTerminologyServer, IWorkerContext.ILoggingService loggingService, boolean THO) {
+    public ValidationEngineBuilder(String terminologyCachePath, String userAgent, String version, String txServer, String txLog, FhirPublication txVersion, TimeTracker timeTracker, boolean canRunWithoutTerminologyServer, ILoggingService loggingService, boolean THO) {
       this.terminologyCachePath = terminologyCachePath;
       this.userAgent = userAgent;
       this.version = version;
@@ -431,7 +432,7 @@ public class ValidationEngine implements IValidatorResourceFetcher, IValidationP
    *
    * @see IgLoader#loadIgSource(String, boolean, boolean) loadIgSource for detailed description of the src parameter
    */
-  private void loadCoreDefinitions(String src, boolean recursive, String terminologyCachePath, String userAgent, TimeTracker tt, IWorkerContext.ILoggingService loggingService) throws FHIRException, IOException {
+  private void loadCoreDefinitions(String src, boolean recursive, String terminologyCachePath, String userAgent, TimeTracker tt, ILoggingService loggingService) throws FHIRException, IOException {
     NpmPackage npm = getPcm().loadPackage(src, null);
     if (npm != null) {
       version = npm.fhirVersion();