diff --git a/buildSrc/src/main/groovy/org/apache/beam/gradle/BeamModulePlugin.groovy b/buildSrc/src/main/groovy/org/apache/beam/gradle/BeamModulePlugin.groovy
index 5efe2d772034..9133795f702f 100644
--- a/buildSrc/src/main/groovy/org/apache/beam/gradle/BeamModulePlugin.groovy
+++ b/buildSrc/src/main/groovy/org/apache/beam/gradle/BeamModulePlugin.groovy
@@ -398,7 +398,7 @@ class BeamModulePlugin implements Plugin<Project> {
 
     // Automatically use the official release version if we are performing a release
     // otherwise append '-SNAPSHOT'
-    project.version = '2.45.20'
+    project.version = '2.45.21'
     if (isLinkedin(project)) {
       project.ext.mavenGroupId = 'com.linkedin.beam'
     }
diff --git a/gradle.properties b/gradle.properties
index 21645e307992..2667e4b5ee4d 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -30,8 +30,8 @@ signing.gnupg.useLegacyGpg=true
 # buildSrc/src/main/groovy/org/apache/beam/gradle/BeamModulePlugin.groovy.
 # To build a custom Beam version make sure you change it in both places, see
 # https://github.com/apache/beam/issues/21302.
-version=2.45.20
-sdk_version=2.45.20
+version=2.45.21
+sdk_version=2.45.21
 
 javaVersion=1.8
 
diff --git a/sdks/java/core/src/main/java/org/apache/beam/sdk/options/CustomPipelineOptionsInitializer.java b/sdks/java/core/src/main/java/org/apache/beam/sdk/options/CustomPipelineOptionsInitializer.java
index b2b05b4881cc..31c9966a0340 100644
--- a/sdks/java/core/src/main/java/org/apache/beam/sdk/options/CustomPipelineOptionsInitializer.java
+++ b/sdks/java/core/src/main/java/org/apache/beam/sdk/options/CustomPipelineOptionsInitializer.java
@@ -1,3 +1,20 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 package org.apache.beam.sdk.options;
 
 import java.util.Iterator;
@@ -6,19 +23,16 @@
 import org.checkerframework.checker.initialization.qual.Initialized;
 import org.checkerframework.checker.nullness.qual.Nullable;
 
-
 /**
- * Interface to support offspring wire-in for Li: if input class is a
- * customized pipelineOptions created by an offspring factory,
- * the pipelineOptions will be initialized.
- *
+ * Interface to support offspring wire-in for Li: if input class is a customized pipelineOptions
+ * created by an offspring factory, the pipelineOptions will be initialized.
  */
 @SuppressWarnings("rawtypes")
 public interface CustomPipelineOptionsInitializer<T> {
   T init(T pipelineOptions, Class<T> clazz);
 
   /**
-   * Inject the implementation for the interface
+   * Inject the implementation for the interface.
    * <p>Usage:
    *
    * <pre>{@code
@@ -34,10 +48,9 @@ interface Registrar {
     CustomPipelineOptionsInitializer create();
   }
 
-
   static @Initialized @Nullable CustomPipelineOptionsInitializer get() {
-    final Iterator<CustomPipelineOptionsInitializer.Registrar>
-        initializer = ServiceLoader.load(CustomPipelineOptionsInitializer.Registrar.class).iterator();
+    final Iterator<CustomPipelineOptionsInitializer.Registrar> initializer =
+        ServiceLoader.load(CustomPipelineOptionsInitializer.Registrar.class).iterator();
     return initializer.hasNext() ? Iterators.getOnlyElement(initializer).create() : null;
   }
 }
diff --git a/sdks/java/core/src/main/java/org/apache/beam/sdk/options/ProxyInvocationHandler.java b/sdks/java/core/src/main/java/org/apache/beam/sdk/options/ProxyInvocationHandler.java
index 53cc62a5ceca..dab71ce7ce27 100644
--- a/sdks/java/core/src/main/java/org/apache/beam/sdk/options/ProxyInvocationHandler.java
+++ b/sdks/java/core/src/main/java/org/apache/beam/sdk/options/ProxyInvocationHandler.java
@@ -196,7 +196,7 @@ public Object invoke(Object proxy, Method method, Object[] args) {
     } else if (args != null && "as".equals(method.getName()) && args[0] instanceof Class) {
       @SuppressWarnings("unchecked")
       Class<? extends PipelineOptions> clazz = (Class<? extends PipelineOptions>) args[0];
-      return as(clazz, (PipelineOptions)proxy); // LI-specific change to wire in offspring
+      return as(clazz, (PipelineOptions) proxy); // LI-specific change to wire in offspring
     } else if (args != null
         && "populateDisplayData".equals(method.getName())
         && args[0] instanceof DisplayData.Builder) {
diff --git a/sdks/java/core/src/main/java/org/apache/beam/sdk/schemas/utils/AvroUtils.java b/sdks/java/core/src/main/java/org/apache/beam/sdk/schemas/utils/AvroUtils.java
index 28f231432c71..be387425f511 100644
--- a/sdks/java/core/src/main/java/org/apache/beam/sdk/schemas/utils/AvroUtils.java
+++ b/sdks/java/core/src/main/java/org/apache/beam/sdk/schemas/utils/AvroUtils.java
@@ -971,7 +971,10 @@ private static org.apache.avro.Schema getFieldSchema(
           baseType =
               org.apache.avro.Schema.createUnion(
                   oneOfType.getOneOfSchema().getFields().stream()
-                      .map(x -> getFieldSchema(x.getType(), x.getName(), namespace))
+                      .map(
+                          x ->
+                              getFieldSchema(
+                                  x.getType().withNullable(false), x.getName(), namespace))
                       .collect(Collectors.toList()));
         } else if ("DATE".equals(identifier) || SqlTypes.DATE.getIdentifier().equals(identifier)) {
           baseType = LogicalTypes.date().addToSchema(org.apache.avro.Schema.create(Type.INT));
diff --git a/sdks/java/core/src/test/java/org/apache/beam/sdk/schemas/utils/AvroUtilsTest.java b/sdks/java/core/src/test/java/org/apache/beam/sdk/schemas/utils/AvroUtilsTest.java
index b8a13770c869..4616fd487ebd 100644
--- a/sdks/java/core/src/test/java/org/apache/beam/sdk/schemas/utils/AvroUtilsTest.java
+++ b/sdks/java/core/src/test/java/org/apache/beam/sdk/schemas/utils/AvroUtilsTest.java
@@ -930,4 +930,35 @@ public FieldType getBaseType() {
       return base;
     }
   }
+
+  private static final String UNION_SCHEMA =
+      "{"
+          + "\"name\" : \"test\","
+          + "\"type\" : \"record\","
+          + "\"fields\" : ["
+          + "{\"name\" : \"Entity\","
+          + " \"type\" : ["
+          + " {\"type\" : \"record\","
+          + "  \"name\" : \"MemberClient\","
+          + "  \"fields\" : ["
+          + "   {\"name\" : \"member\","
+          + "    \"type\" : \"string\"}]"
+          + " },"
+          + " {\"type\" : \"record\","
+          + "  \"name\" : \"OrganizationClient\","
+          + "  \"fields\" : ["
+          + "    {\"name\" : \"organization\","
+          + "     \"type\" : \"string\"},"
+          + "    {\"name\" : \"displayName\","
+          + "     \"type\" : [ \"null\", \"string\" ]}]"
+          + " }]}"
+          + "]}";
+
+  @Test
+  public void testUnion() {
+    org.apache.avro.Schema schema = org.apache.avro.Schema.parse(UNION_SCHEMA);
+    Schema beamSchema = AvroUtils.toBeamSchema(schema);
+    org.apache.avro.Schema convertedSchema = AvroUtils.toAvroSchema(beamSchema);
+    assertEquals(Type.UNION, convertedSchema.getField("Entity").schema().getType());
+  }
 }