diff --git a/java-codegen/src/main/java/org/opensearch/client/codegen/model/ShapeRenderingContext.java b/java-codegen/src/main/java/org/opensearch/client/codegen/model/ShapeRenderingContext.java
index 7e14698668..097dee806c 100644
--- a/java-codegen/src/main/java/org/opensearch/client/codegen/model/ShapeRenderingContext.java
+++ b/java-codegen/src/main/java/org/opensearch/client/codegen/model/ShapeRenderingContext.java
@@ -12,7 +12,6 @@
 import java.util.Objects;
 import java.util.function.Function;
 import javax.annotation.Nonnull;
-import org.jetbrains.annotations.NotNull;
 import org.opensearch.client.codegen.renderer.JavaCodeFormatter;
 import org.opensearch.client.codegen.renderer.TemplateLoader;
 import org.opensearch.client.codegen.renderer.TemplateRenderer;
@@ -84,7 +83,7 @@ private Builder() {
         }
 
         @Override
-        protected @NotNull Builder self() {
+        protected @Nonnull Builder self() {
             return this;
         }
 
diff --git a/java-codegen/src/main/java/org/opensearch/client/codegen/model/Type.java b/java-codegen/src/main/java/org/opensearch/client/codegen/model/Type.java
index 9c1db57814..18f5eee2d1 100644
--- a/java-codegen/src/main/java/org/opensearch/client/codegen/model/Type.java
+++ b/java-codegen/src/main/java/org/opensearch/client/codegen/model/Type.java
@@ -15,7 +15,6 @@
 import java.util.Set;
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
-import org.checkerframework.checker.nullness.qual.NonNull;
 import org.opensearch.client.codegen.renderer.lambdas.TypeIsDefinedLambda;
 import org.opensearch.client.codegen.renderer.lambdas.TypeQueryParamifyLambda;
 import org.opensearch.client.codegen.renderer.lambdas.TypeSerializerLambda;
@@ -48,7 +47,7 @@ public static Builder builder() {
     }
 
     @Nullable
-    private final String package_;
+    private final String packageName;
     @Nonnull
     private final String name;
     @Nullable
@@ -56,14 +55,14 @@ public static Builder builder() {
     private final boolean isEnum;
 
     private Type(Builder builder) {
-        this.package_ = builder.package_;
+        this.packageName = builder.packageName;
         this.name = Strings.requireNonBlank(builder.name, "name must not be blank");
         this.typeParams = builder.typeParams;
         this.isEnum = builder.isEnum;
     }
 
     public Builder toBuilder() {
-        return new Builder().withPackage(package_).withName(name).withTypeParameters(typeParams).isEnum(isEnum);
+        return new Builder().withPackage(packageName).withName(name).withTypeParameters(typeParams).isEnum(isEnum);
     }
 
     @Override
@@ -178,7 +177,7 @@ public Type getBuilderFnType() {
     }
 
     public Type getNestedType(String name) {
-        return builder().withPackage(package_).withName(this.name + "." + name).build();
+        return builder().withPackage(packageName).withName(this.name + "." + name).build();
     }
 
     public Mustache.Lambda serializer() {
@@ -190,9 +189,9 @@ public Mustache.Lambda directSerializer() {
     }
 
     public void getRequiredImports(Set<String> imports, String currentPkg) {
-        if (package_ != null && !package_.equals(Java.Lang.PACKAGE) && !package_.equals(currentPkg)) {
+        if (packageName != null && !packageName.equals(Java.Lang.PACKAGE) && !packageName.equals(currentPkg)) {
             var dotIdx = name.indexOf('.');
-            imports.add(package_ + '.' + (dotIdx > 0 ? name.substring(0, dotIdx) : name));
+            imports.add(packageName + '.' + (dotIdx > 0 ? name.substring(0, dotIdx) : name));
         }
         if (typeParams != null) {
             for (Type arg : typeParams) {
@@ -214,7 +213,7 @@ public Mustache.Lambda isDefined() {
     }
 
     public static final class Builder extends ObjectBuilderBase<Type, Builder> {
-        private String package_;
+        private String packageName;
         private String name;
         private Type[] typeParams;
         private boolean isEnum;
@@ -224,13 +223,13 @@ private Builder() {
         }
 
         @Override
-        protected @NonNull Builder self() {
+        protected @Nonnull Builder self() {
             return this;
         }
 
         @Nonnull
-        public Builder withPackage(@Nullable String package_) {
-            this.package_ = package_;
+        public Builder withPackage(@Nullable String packageName) {
+            this.packageName = packageName;
             return this;
         }
 
diff --git a/java-codegen/src/main/java/org/opensearch/client/codegen/model/TypeParameterDefinition.java b/java-codegen/src/main/java/org/opensearch/client/codegen/model/TypeParameterDefinition.java
index 991bcbc1ec..1fb3e9d656 100644
--- a/java-codegen/src/main/java/org/opensearch/client/codegen/model/TypeParameterDefinition.java
+++ b/java-codegen/src/main/java/org/opensearch/client/codegen/model/TypeParameterDefinition.java
@@ -10,7 +10,6 @@
 
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
-import org.jetbrains.annotations.NotNull;
 import org.opensearch.client.codegen.utils.ObjectBuilderBase;
 import org.opensearch.client.codegen.utils.Strings;
 
@@ -18,11 +17,11 @@ public final class TypeParameterDefinition {
     @Nonnull
     private final String name;
     @Nullable
-    private final Type extends_;
+    private final Type extendsType;
 
     private TypeParameterDefinition(Builder builder) {
         this.name = Strings.requireNonBlank(builder.name, "name must not be blank");
-        this.extends_ = builder.extends_;
+        this.extendsType = builder.extendsType;
     }
 
     @Nonnull
@@ -32,12 +31,12 @@ public String getName() {
 
     @Nullable
     public Type getExtends() {
-        return extends_;
+        return extendsType;
     }
 
     @Override
     public String toString() {
-        return name + (extends_ != null ? " extends " + extends_ : "");
+        return name + (extendsType != null ? " extends " + extendsType : "");
     }
 
     public static Builder builder() {
@@ -46,14 +45,14 @@ public static Builder builder() {
 
     public static final class Builder extends ObjectBuilderBase<TypeParameterDefinition, Builder> {
         private String name;
-        private Type extends_;
+        private Type extendsType;
 
         private Builder() {
             super(TypeParameterDefinition::new);
         }
 
         @Override
-        protected @NotNull Builder self() {
+        protected @Nonnull Builder self() {
             return this;
         }
 
@@ -65,7 +64,7 @@ public Builder withName(@Nonnull String name) {
 
         @Nonnull
         public Builder withExtends(@Nullable Type type) {
-            this.extends_ = type;
+            this.extendsType = type;
             return this;
         }
     }
diff --git a/java-codegen/src/main/java/org/opensearch/client/codegen/openapi/OpenApiSchema.java b/java-codegen/src/main/java/org/opensearch/client/codegen/openapi/OpenApiSchema.java
index 980145a4be..b301160c53 100644
--- a/java-codegen/src/main/java/org/opensearch/client/codegen/openapi/OpenApiSchema.java
+++ b/java-codegen/src/main/java/org/opensearch/client/codegen/openapi/OpenApiSchema.java
@@ -21,7 +21,6 @@
 import java.util.stream.Collectors;
 import javax.annotation.Nonnull;
 import javax.annotation.Nullable;
-import org.jetbrains.annotations.NotNull;
 import org.opensearch.client.codegen.utils.Lists;
 import org.opensearch.client.codegen.utils.Maps;
 import org.opensearch.client.codegen.utils.ObjectBuilderBase;
@@ -360,7 +359,7 @@ private Builder() {
         }
 
         @Override
-        protected @NotNull Builder self() {
+        protected @Nonnull Builder self() {
             return this;
         }