diff --git a/typespec-extension/changelog.md b/typespec-extension/changelog.md
index 4ede67dca8..a7634ba380 100644
--- a/typespec-extension/changelog.md
+++ b/typespec-extension/changelog.md
@@ -1,5 +1,11 @@
 # Release History
 
+## 0.15.18 (2024-05-13)
+
+Compatible with compiler 0.56.
+
+- `enum` is closed enum.
+
 ## 0.15.17 (2024-05-11)
 
 Compatible with compiler 0.56.
diff --git a/typespec-extension/package-lock.json b/typespec-extension/package-lock.json
index d3aa8cb160..00c9a0de0f 100644
--- a/typespec-extension/package-lock.json
+++ b/typespec-extension/package-lock.json
@@ -1,12 +1,12 @@
 {
   "name": "@azure-tools/typespec-java",
-  "version": "0.15.17",
+  "version": "0.15.18",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "@azure-tools/typespec-java",
-      "version": "0.15.17",
+      "version": "0.15.18",
       "license": "MIT",
       "dependencies": {
         "@autorest/codemodel": "~4.20.0",
diff --git a/typespec-extension/package.json b/typespec-extension/package.json
index e4125e5b91..baaef548d2 100644
--- a/typespec-extension/package.json
+++ b/typespec-extension/package.json
@@ -1,6 +1,6 @@
 {
   "name": "@azure-tools/typespec-java",
-  "version": "0.15.17",
+  "version": "0.15.18",
   "description": "TypeSpec library for emitting Java client from the TypeSpec REST protocol binding",
   "keywords": [
     "TypeSpec"
diff --git a/typespec-extension/src/code-model-builder.ts b/typespec-extension/src/code-model-builder.ts
index 6300a0f725..d35258b88e 100644
--- a/typespec-extension/src/code-model-builder.ts
+++ b/typespec-extension/src/code-model-builder.ts
@@ -61,7 +61,6 @@ import { Version, getAddedOnVersions, getVersion } from "@typespec/versioning";
 import {
   isPollingLocation,
   getPagedResult,
-  isFixed,
   getLroMetadata,
   getUnionAsEnum,
   UnionEnum,
@@ -1726,7 +1725,7 @@ export class CodeModelBuilder {
         return this.processConstantSchemaForLiteral(type, nameHint);
 
       case "Enum":
-        return this.processChoiceSchema(type, this.getName(type), isFixed(this.program, type));
+        return this.processChoiceSchema(type, this.getName(type), true);
 
       case "Union":
         return this.processUnionSchema(type, this.getName(type, nameHint));
diff --git a/typespec-tests/package.json b/typespec-tests/package.json
index d7f3b0c157..45e7d72583 100644
--- a/typespec-tests/package.json
+++ b/typespec-tests/package.json
@@ -10,7 +10,7 @@
   },
   "dependencies": {
     "@azure-tools/cadl-ranch-specs": "0.33.4",
-    "@azure-tools/typespec-java": "file:/../typespec-extension/azure-tools-typespec-java-0.15.17.tgz"
+    "@azure-tools/typespec-java": "file:/../typespec-extension/azure-tools-typespec-java-0.15.18.tgz"
   },
   "devDependencies": {
     "@typespec/prettier-plugin-typespec": "~0.56.0",
diff --git a/typespec-tests/src/main/java/com/cadl/longrunning/models/OperationState.java b/typespec-tests/src/main/java/com/cadl/longrunning/models/OperationState.java
index 30784b9a26..9313f4f237 100644
--- a/typespec-tests/src/main/java/com/cadl/longrunning/models/OperationState.java
+++ b/typespec-tests/src/main/java/com/cadl/longrunning/models/OperationState.java
@@ -4,72 +4,68 @@
 
 package com.cadl.longrunning.models;
 
-import com.azure.core.annotation.Generated;
-import com.azure.core.util.ExpandableStringEnum;
-import java.util.Collection;
-
 /**
  * Enum describing allowed operation states.
  */
-public final class OperationState extends ExpandableStringEnum<OperationState> {
+public enum OperationState {
     /**
      * The operation has not started.
      */
-    @Generated
-    public static final OperationState NOT_STARTED = fromString("NotStarted");
+    NOT_STARTED("NotStarted"),
 
     /**
      * The operation is in progress.
      */
-    @Generated
-    public static final OperationState RUNNING = fromString("Running");
+    RUNNING("Running"),
 
     /**
      * The operation has completed successfully.
      */
-    @Generated
-    public static final OperationState SUCCEEDED = fromString("Succeeded");
+    SUCCEEDED("Succeeded"),
 
     /**
      * The operation has failed.
      */
-    @Generated
-    public static final OperationState FAILED = fromString("Failed");
+    FAILED("Failed"),
 
     /**
      * The operation has been canceled by the user.
      */
-    @Generated
-    public static final OperationState CANCELED = fromString("Canceled");
+    CANCELED("Canceled");
 
     /**
-     * Creates a new instance of OperationState value.
-     * 
-     * @deprecated Use the {@link #fromString(String)} factory method.
+     * The actual serialized value for a OperationState instance.
      */
-    @Generated
-    @Deprecated
-    public OperationState() {
+    private final String value;
+
+    OperationState(String value) {
+        this.value = value;
     }
 
     /**
-     * Creates or finds a OperationState from its string representation.
+     * Parses a serialized value to a OperationState instance.
      * 
-     * @param name a name to look for.
-     * @return the corresponding OperationState.
+     * @param value the serialized value to parse.
+     * @return the parsed OperationState object, or null if unable to parse.
      */
-    @Generated
-    public static OperationState fromString(String name) {
-        return fromString(name, OperationState.class);
+    public static OperationState fromString(String value) {
+        if (value == null) {
+            return null;
+        }
+        OperationState[] items = OperationState.values();
+        for (OperationState item : items) {
+            if (item.toString().equalsIgnoreCase(value)) {
+                return item;
+            }
+        }
+        return null;
     }
 
     /**
-     * Gets known OperationState values.
-     * 
-     * @return known OperationState values.
+     * {@inheritDoc}
      */
-    @Generated
-    public static Collection<OperationState> values() {
-        return values(OperationState.class);
+    @Override
+    public String toString() {
+        return this.value;
     }
 }
diff --git a/typespec-tests/src/main/java/com/cadl/response/models/OperationState.java b/typespec-tests/src/main/java/com/cadl/response/models/OperationState.java
index ce23be521f..f8874d5a62 100644
--- a/typespec-tests/src/main/java/com/cadl/response/models/OperationState.java
+++ b/typespec-tests/src/main/java/com/cadl/response/models/OperationState.java
@@ -4,72 +4,68 @@
 
 package com.cadl.response.models;
 
-import com.azure.core.annotation.Generated;
-import com.azure.core.util.ExpandableStringEnum;
-import java.util.Collection;
-
 /**
  * Enum describing allowed operation states.
  */
-public final class OperationState extends ExpandableStringEnum<OperationState> {
+public enum OperationState {
     /**
      * The operation has not started.
      */
-    @Generated
-    public static final OperationState NOT_STARTED = fromString("NotStarted");
+    NOT_STARTED("NotStarted"),
 
     /**
      * The operation is in progress.
      */
-    @Generated
-    public static final OperationState RUNNING = fromString("Running");
+    RUNNING("Running"),
 
     /**
      * The operation has completed successfully.
      */
-    @Generated
-    public static final OperationState SUCCEEDED = fromString("Succeeded");
+    SUCCEEDED("Succeeded"),
 
     /**
      * The operation has failed.
      */
-    @Generated
-    public static final OperationState FAILED = fromString("Failed");
+    FAILED("Failed"),
 
     /**
      * The operation has been canceled by the user.
      */
-    @Generated
-    public static final OperationState CANCELED = fromString("Canceled");
+    CANCELED("Canceled");
 
     /**
-     * Creates a new instance of OperationState value.
-     * 
-     * @deprecated Use the {@link #fromString(String)} factory method.
+     * The actual serialized value for a OperationState instance.
      */
-    @Generated
-    @Deprecated
-    public OperationState() {
+    private final String value;
+
+    OperationState(String value) {
+        this.value = value;
     }
 
     /**
-     * Creates or finds a OperationState from its string representation.
+     * Parses a serialized value to a OperationState instance.
      * 
-     * @param name a name to look for.
-     * @return the corresponding OperationState.
+     * @param value the serialized value to parse.
+     * @return the parsed OperationState object, or null if unable to parse.
      */
-    @Generated
-    public static OperationState fromString(String name) {
-        return fromString(name, OperationState.class);
+    public static OperationState fromString(String value) {
+        if (value == null) {
+            return null;
+        }
+        OperationState[] items = OperationState.values();
+        for (OperationState item : items) {
+            if (item.toString().equalsIgnoreCase(value)) {
+                return item;
+            }
+        }
+        return null;
     }
 
     /**
-     * Gets known OperationState values.
-     * 
-     * @return known OperationState values.
+     * {@inheritDoc}
      */
-    @Generated
-    public static Collection<OperationState> values() {
-        return values(OperationState.class);
+    @Override
+    public String toString() {
+        return this.value;
     }
 }
diff --git a/typespec-tests/src/main/java/com/versioning/added/models/EnumV1.java b/typespec-tests/src/main/java/com/versioning/added/models/EnumV1.java
index 469a70ce4f..35a2adf324 100644
--- a/typespec-tests/src/main/java/com/versioning/added/models/EnumV1.java
+++ b/typespec-tests/src/main/java/com/versioning/added/models/EnumV1.java
@@ -4,54 +4,53 @@
 
 package com.versioning.added.models;
 
-import com.azure.core.annotation.Generated;
-import com.azure.core.util.ExpandableStringEnum;
-import java.util.Collection;
-
 /**
  * Defines values for EnumV1.
  */
-public final class EnumV1 extends ExpandableStringEnum<EnumV1> {
+public enum EnumV1 {
     /**
-     * Static value enumMemberV1 for EnumV1.
+     * Enum value enumMemberV1.
      */
-    @Generated
-    public static final EnumV1 ENUM_MEMBER_V1 = fromString("enumMemberV1");
+    ENUM_MEMBER_V1("enumMemberV1"),
 
     /**
-     * Static value enumMemberV2 for EnumV1.
+     * Enum value enumMemberV2.
      */
-    @Generated
-    public static final EnumV1 ENUM_MEMBER_V2 = fromString("enumMemberV2");
+    ENUM_MEMBER_V2("enumMemberV2");
 
     /**
-     * Creates a new instance of EnumV1 value.
-     * 
-     * @deprecated Use the {@link #fromString(String)} factory method.
+     * The actual serialized value for a EnumV1 instance.
      */
-    @Generated
-    @Deprecated
-    public EnumV1() {
+    private final String value;
+
+    EnumV1(String value) {
+        this.value = value;
     }
 
     /**
-     * Creates or finds a EnumV1 from its string representation.
+     * Parses a serialized value to a EnumV1 instance.
      * 
-     * @param name a name to look for.
-     * @return the corresponding EnumV1.
+     * @param value the serialized value to parse.
+     * @return the parsed EnumV1 object, or null if unable to parse.
      */
-    @Generated
-    public static EnumV1 fromString(String name) {
-        return fromString(name, EnumV1.class);
+    public static EnumV1 fromString(String value) {
+        if (value == null) {
+            return null;
+        }
+        EnumV1[] items = EnumV1.values();
+        for (EnumV1 item : items) {
+            if (item.toString().equalsIgnoreCase(value)) {
+                return item;
+            }
+        }
+        return null;
     }
 
     /**
-     * Gets known EnumV1 values.
-     * 
-     * @return known EnumV1 values.
+     * {@inheritDoc}
      */
-    @Generated
-    public static Collection<EnumV1> values() {
-        return values(EnumV1.class);
+    @Override
+    public String toString() {
+        return this.value;
     }
 }
diff --git a/typespec-tests/src/main/java/com/versioning/added/models/EnumV2.java b/typespec-tests/src/main/java/com/versioning/added/models/EnumV2.java
index 4cdef517c5..0b9382c290 100644
--- a/typespec-tests/src/main/java/com/versioning/added/models/EnumV2.java
+++ b/typespec-tests/src/main/java/com/versioning/added/models/EnumV2.java
@@ -4,48 +4,48 @@
 
 package com.versioning.added.models;
 
-import com.azure.core.annotation.Generated;
-import com.azure.core.util.ExpandableStringEnum;
-import java.util.Collection;
-
 /**
  * Defines values for EnumV2.
  */
-public final class EnumV2 extends ExpandableStringEnum<EnumV2> {
+public enum EnumV2 {
     /**
-     * Static value enumMember for EnumV2.
+     * Enum value enumMember.
      */
-    @Generated
-    public static final EnumV2 ENUM_MEMBER = fromString("enumMember");
+    ENUM_MEMBER("enumMember");
 
     /**
-     * Creates a new instance of EnumV2 value.
-     * 
-     * @deprecated Use the {@link #fromString(String)} factory method.
+     * The actual serialized value for a EnumV2 instance.
      */
-    @Generated
-    @Deprecated
-    public EnumV2() {
+    private final String value;
+
+    EnumV2(String value) {
+        this.value = value;
     }
 
     /**
-     * Creates or finds a EnumV2 from its string representation.
+     * Parses a serialized value to a EnumV2 instance.
      * 
-     * @param name a name to look for.
-     * @return the corresponding EnumV2.
+     * @param value the serialized value to parse.
+     * @return the parsed EnumV2 object, or null if unable to parse.
      */
-    @Generated
-    public static EnumV2 fromString(String name) {
-        return fromString(name, EnumV2.class);
+    public static EnumV2 fromString(String value) {
+        if (value == null) {
+            return null;
+        }
+        EnumV2[] items = EnumV2.values();
+        for (EnumV2 item : items) {
+            if (item.toString().equalsIgnoreCase(value)) {
+                return item;
+            }
+        }
+        return null;
     }
 
     /**
-     * Gets known EnumV2 values.
-     * 
-     * @return known EnumV2 values.
+     * {@inheritDoc}
      */
-    @Generated
-    public static Collection<EnumV2> values() {
-        return values(EnumV2.class);
+    @Override
+    public String toString() {
+        return this.value;
     }
 }
diff --git a/typespec-tests/src/main/java/com/versioning/removed/models/EnumV2.java b/typespec-tests/src/main/java/com/versioning/removed/models/EnumV2.java
index 4ee52e10bd..9a64c307a4 100644
--- a/typespec-tests/src/main/java/com/versioning/removed/models/EnumV2.java
+++ b/typespec-tests/src/main/java/com/versioning/removed/models/EnumV2.java
@@ -4,48 +4,48 @@
 
 package com.versioning.removed.models;
 
-import com.azure.core.annotation.Generated;
-import com.azure.core.util.ExpandableStringEnum;
-import java.util.Collection;
-
 /**
  * Defines values for EnumV2.
  */
-public final class EnumV2 extends ExpandableStringEnum<EnumV2> {
+public enum EnumV2 {
     /**
-     * Static value enumMemberV2 for EnumV2.
+     * Enum value enumMemberV2.
      */
-    @Generated
-    public static final EnumV2 ENUM_MEMBER_V2 = fromString("enumMemberV2");
+    ENUM_MEMBER_V2("enumMemberV2");
 
     /**
-     * Creates a new instance of EnumV2 value.
-     * 
-     * @deprecated Use the {@link #fromString(String)} factory method.
+     * The actual serialized value for a EnumV2 instance.
      */
-    @Generated
-    @Deprecated
-    public EnumV2() {
+    private final String value;
+
+    EnumV2(String value) {
+        this.value = value;
     }
 
     /**
-     * Creates or finds a EnumV2 from its string representation.
+     * Parses a serialized value to a EnumV2 instance.
      * 
-     * @param name a name to look for.
-     * @return the corresponding EnumV2.
+     * @param value the serialized value to parse.
+     * @return the parsed EnumV2 object, or null if unable to parse.
      */
-    @Generated
-    public static EnumV2 fromString(String name) {
-        return fromString(name, EnumV2.class);
+    public static EnumV2 fromString(String value) {
+        if (value == null) {
+            return null;
+        }
+        EnumV2[] items = EnumV2.values();
+        for (EnumV2 item : items) {
+            if (item.toString().equalsIgnoreCase(value)) {
+                return item;
+            }
+        }
+        return null;
     }
 
     /**
-     * Gets known EnumV2 values.
-     * 
-     * @return known EnumV2 values.
+     * {@inheritDoc}
      */
-    @Generated
-    public static Collection<EnumV2> values() {
-        return values(EnumV2.class);
+    @Override
+    public String toString() {
+        return this.value;
     }
 }
diff --git a/typespec-tests/src/main/java/com/versioning/renamedfrom/models/NewEnum.java b/typespec-tests/src/main/java/com/versioning/renamedfrom/models/NewEnum.java
index d5967e7d01..7206ee2585 100644
--- a/typespec-tests/src/main/java/com/versioning/renamedfrom/models/NewEnum.java
+++ b/typespec-tests/src/main/java/com/versioning/renamedfrom/models/NewEnum.java
@@ -4,48 +4,48 @@
 
 package com.versioning.renamedfrom.models;
 
-import com.azure.core.annotation.Generated;
-import com.azure.core.util.ExpandableStringEnum;
-import java.util.Collection;
-
 /**
  * Defines values for NewEnum.
  */
-public final class NewEnum extends ExpandableStringEnum<NewEnum> {
+public enum NewEnum {
     /**
-     * Static value newEnumMember for NewEnum.
+     * Enum value newEnumMember.
      */
-    @Generated
-    public static final NewEnum NEW_ENUM_MEMBER = fromString("newEnumMember");
+    NEW_ENUM_MEMBER("newEnumMember");
 
     /**
-     * Creates a new instance of NewEnum value.
-     * 
-     * @deprecated Use the {@link #fromString(String)} factory method.
+     * The actual serialized value for a NewEnum instance.
      */
-    @Generated
-    @Deprecated
-    public NewEnum() {
+    private final String value;
+
+    NewEnum(String value) {
+        this.value = value;
     }
 
     /**
-     * Creates or finds a NewEnum from its string representation.
+     * Parses a serialized value to a NewEnum instance.
      * 
-     * @param name a name to look for.
-     * @return the corresponding NewEnum.
+     * @param value the serialized value to parse.
+     * @return the parsed NewEnum object, or null if unable to parse.
      */
-    @Generated
-    public static NewEnum fromString(String name) {
-        return fromString(name, NewEnum.class);
+    public static NewEnum fromString(String value) {
+        if (value == null) {
+            return null;
+        }
+        NewEnum[] items = NewEnum.values();
+        for (NewEnum item : items) {
+            if (item.toString().equalsIgnoreCase(value)) {
+                return item;
+            }
+        }
+        return null;
     }
 
     /**
-     * Gets known NewEnum values.
-     * 
-     * @return known NewEnum values.
+     * {@inheritDoc}
      */
-    @Generated
-    public static Collection<NewEnum> values() {
-        return values(NewEnum.class);
+    @Override
+    public String toString() {
+        return this.value;
     }
 }
diff --git a/typespec-tests/tsp/enum.tsp b/typespec-tests/tsp/enum.tsp
index 1fff3f6e68..54d21fbec7 100644
--- a/typespec-tests/tsp/enum.tsp
+++ b/typespec-tests/tsp/enum.tsp
@@ -12,7 +12,6 @@ using Azure.ClientGenerator.Core;
 namespace Cadl.EnumService;
 
 #suppress "@azure-tools/typespec-azure-core/use-extensible-enum" "For testing"
-@fixed
 enum Color {
   Red,
   Blue,
@@ -38,14 +37,12 @@ union PriorityModel {
 }
 
 #suppress "@azure-tools/typespec-azure-core/use-extensible-enum" "For testing"
-@fixed
 enum Priority {
   High: 100,
   Low: 0,
 }
 
 #suppress "@azure-tools/typespec-azure-core/use-extensible-enum" "For testing"
-@fixed
 enum Unit {
   Grams: 1,
   KiloGrams: 0.001,
@@ -53,7 +50,6 @@ enum Unit {
 }
 
 #suppress "@azure-tools/typespec-azure-core/use-extensible-enum" "For testing"
-@fixed
 enum OperationStateValues {
   Running,
   Completed,
diff --git a/typespec-tests/tsp/internal.tsp b/typespec-tests/tsp/internal.tsp
index 8161bd910a..95e1981cc3 100644
--- a/typespec-tests/tsp/internal.tsp
+++ b/typespec-tests/tsp/internal.tsp
@@ -60,7 +60,6 @@ model StandAloneUnion {
 // Color and ColorModel will be generated in implementation.models package
 #suppress "@azure-tools/typespec-azure-core/use-extensible-enum" "For testing"
 @access(Access.internal)
-@fixed
 enum Color {
   Red,
   Blue,
diff --git a/typespec-tests/tsp/naming.tsp b/typespec-tests/tsp/naming.tsp
index ba4011ea31..3b5c86726e 100644
--- a/typespec-tests/tsp/naming.tsp
+++ b/typespec-tests/tsp/naming.tsp
@@ -77,7 +77,6 @@ model BytesData extends Data {
 #suppress "@azure-tools/typespec-azure-core/use-extensible-enum" "For testing"
 @summary("summary of Types")
 @doc("description of Types")
-@fixed
 enum TypesModel {
   Blob,
   File,