diff --git a/SdmxBeans/src/main/java/org/sdmxsource/sdmx/sdmxbeans/model/beans/codelist/CodelistBeanImpl.java b/SdmxBeans/src/main/java/org/sdmxsource/sdmx/sdmxbeans/model/beans/codelist/CodelistBeanImpl.java
index 18c8729..6e5f276 100644
--- a/SdmxBeans/src/main/java/org/sdmxsource/sdmx/sdmxbeans/model/beans/codelist/CodelistBeanImpl.java
+++ b/SdmxBeans/src/main/java/org/sdmxsource/sdmx/sdmxbeans/model/beans/codelist/CodelistBeanImpl.java
@@ -54,12 +54,14 @@
 public class CodelistBeanImpl extends ItemSchemeBeanImpl<CodeBean> implements CodelistBean {
     private static final long serialVersionUID = 1L;
 
+    private final Map<String, CodeBean> codeMap;
 
     ///////////////////////////////////////////////////////////////////////////////////////////////////
     ////////////BUILD FROM ITSELF, CREATES STUB BEAN //////////////////////////////////////////////////
     ///////////////////////////////////////////////////////////////////////////////////////////////////
     private CodelistBeanImpl(CodelistBean bean, URL actualLocation, boolean isServiceUrl) {
         super(bean, actualLocation, isServiceUrl);
+        this.codeMap = new HashMap<>();
     }
 
     /**
@@ -72,10 +74,13 @@ private CodelistBeanImpl(CodelistBean bean, URL actualLocation, boolean isServic
     ///////////////////////////////////////////////////////////////////////////////////////////////////
     public CodelistBeanImpl(CodelistMutableBean codelist) {
         super(codelist);
+        codeMap = new HashMap<>();
         try {
             if (codelist.getItems() != null) {
-                for (CodeMutableBean code : codelist.getItems()) {
-                    this.items.add(new CodeBeanImpl(this, code));
+                for (CodeMutableBean mutableCode : codelist.getItems()) {
+                    var code = new CodeBeanImpl(this, mutableCode);
+                    this.items.add(code);
+                    this.codeMap.put(code.getId(), code);
                 }
             }
         } catch (SdmxSemmanticException ex) {
@@ -134,10 +139,13 @@ public CodelistBeanImpl(org.sdmx.resources.sdmxml.schemas.v10.xmlbeans.structure
                 bean.getNameList(),
                 createTertiary(bean.isSetIsExternalReference(), bean.getIsExternalReference()),
                 bean.getAnnotations());
+        this.codeMap = new HashMap<>();
 
         try {
             for (org.sdmx.resources.sdmxml.schemas.v10.xmlbeans.structure.CodeType currentCode : bean.getCodeList()) {
-                items.add(new CodeBeanImpl(this, currentCode));
+                var code = new CodeBeanImpl(this, currentCode);
+                items.add(code);
+                codeMap.put(code.getId(), code);
             }
         } catch (SdmxSemmanticException ex) {
             throw new SdmxSemmanticException(ex, ExceptionCode.BEAN_STRUCTURE_CONSTRUCTION_ERROR, this.getUrn());
@@ -176,10 +184,13 @@ public CodelistBeanImpl(CodeListType bean) {
                 createTertiary(bean.isSetIsExternalReference(), bean.getIsExternalReference()),
                 bean.getAnnotations());
 
+        this.codeMap = new HashMap<>();
 
         try {
             for (CodeType currentCode : bean.getCodeList()) {
-                items.add(new CodeBeanImpl(this, currentCode));
+                var code = new CodeBeanImpl(this, currentCode);
+                items.add(code);
+                codeMap.put(code.getId(), code);
             }
         } catch (SdmxSemmanticException ex) {
             throw new SdmxSemmanticException(ex, ExceptionCode.BEAN_STRUCTURE_CONSTRUCTION_ERROR, this.getUrn());
@@ -205,10 +216,13 @@ public CodelistBeanImpl(CodeListType bean) {
     ///////////////////////////////////////////////////////////////////////////////////////////////////
     public CodelistBeanImpl(CodelistType bean) {
         super(bean, SDMX_STRUCTURE_TYPE.CODE_LIST);
+        this.codeMap = new HashMap<>();
 
         try {
             for (org.sdmx.resources.sdmxml.schemas.v21.structure.CodeType currentCode : bean.getCodeList()) {
-                items.add(new CodeBeanImpl(this, currentCode));
+                var code = new CodeBeanImpl(this, currentCode);
+                items.add(code);
+                codeMap.put(code.getId(), code);
             }
         } catch (SdmxSemmanticException ex) {
             throw new SdmxSemmanticException(ex, ExceptionCode.BEAN_STRUCTURE_CONSTRUCTION_ERROR, this.getUrn());
@@ -255,7 +269,7 @@ private void validate() throws ValidationException {
                 urns.add(code.getUrn());
 
                 if (ObjectUtil.validString(code.getParentCode())) {
-                    CodeBean parentCode = getCode(items, code.getParentCode());
+                    CodeBean parentCode = getCode(code.getParentCode());
                     Set<CodeBean> children;
                     if (parentChildMap.containsKey(parentCode)) {
                         children = parentChildMap.get(parentCode);
@@ -296,13 +310,12 @@ private void recurseParentMap(Set<CodeBean> children, CodeBean parentCode, Map<C
         }
     }
 
-    private CodeBean getCode(List<CodeBean> codes, String id) {
-        for (CodeBean currentCode : codes) {
-            if (currentCode.getId().equals(id)) {
-                return currentCode;
-            }
+    private CodeBean getCode(String id) {
+        CodeBean code = getCodeById(id);
+        if (code == null) {
+            throw new SdmxSemmanticException(ExceptionCode.CAN_NOT_RESOLVE_PARENT, id);
         }
-        throw new SdmxSemmanticException(ExceptionCode.CAN_NOT_RESOLVE_PARENT, id);
+        return code;
     }
 
     ///////////////////////////////////////////////////////////////////////////////////////////////////
@@ -321,11 +334,6 @@ public CodelistMutableBean getMutableInstance() {
 
     @Override
     public CodeBean getCodeById(String id) {
-        for (CodeBean currentCode : items) {
-            if (currentCode.getId().equals(id)) {
-                return currentCode;
-            }
-        }
-        return null;
+        return codeMap.get(id);
     }
 }
diff --git a/SdmxBeans/src/test/java/org/sdmxsource/sdmx/sdmxbeans/test/CodeListSuperBeanTest.java b/SdmxBeans/src/test/java/org/sdmxsource/sdmx/sdmxbeans/test/CodeListSuperBeanTest.java
index d051bc2..646be89 100644
--- a/SdmxBeans/src/test/java/org/sdmxsource/sdmx/sdmxbeans/test/CodeListSuperBeanTest.java
+++ b/SdmxBeans/src/test/java/org/sdmxsource/sdmx/sdmxbeans/test/CodeListSuperBeanTest.java
@@ -1,5 +1,12 @@
 package org.sdmxsource.sdmx.sdmxbeans.test;
 
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.sdmxsource.sdmx.sdmxbeans.data.DataHelper.buildCodelist;
+
+import java.util.List;
+
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
 import org.sdmxsource.sdmx.api.model.beans.codelist.CodeBean;
@@ -9,12 +16,6 @@
 import org.sdmxsource.sdmx.sdmxbeans.model.mutablesuperbeans.codelist.CodelistMutableSuperBeanImpl;
 import org.sdmxsource.sdmx.sdmxbeans.model.superbeans.codelist.CodelistSuperBeanImpl;
 
-import java.util.List;
-
-import static java.util.stream.Collectors.toList;
-import static org.junit.jupiter.api.Assertions.*;
-import static org.sdmxsource.sdmx.sdmxbeans.data.DataHelper.buildCodelist;
-
 public class CodeListSuperBeanTest {
 
     private CodelistBean codelistBean;
@@ -22,7 +23,7 @@ public class CodeListSuperBeanTest {
 
     @BeforeEach
     public void setup() {
-        codelistBean = buildCodelist(10).getImmutableInstance();
+        codelistBean = buildCodelist(5_000).getImmutableInstance();
         codelistSuperBean = new CodelistSuperBeanImpl(codelistBean);
     }
 
@@ -40,7 +41,7 @@ public void shouldCheckExceptionForInvalidCodeId() {
     public void shouldCheckNumberOfCodes() {
         List<CodeBean> codesWithoutParent = codelistBean.getItems().stream()
                 .filter(code -> code.getParentCode() == null)
-                .collect(toList());
+                .toList();
 
         assertEquals(codesWithoutParent.size(), codelistSuperBean.getCodes().size());
     }