code: /*
   * Copyright (c) 2016-present, RxJava Contributors.
   *
   * Licensed 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 io.reactivex.rxjava3.annotations;
  
  import static java.lang.annotation.ElementType.*;
  import static java.lang.annotation.RetentionPolicy.CLASS;
  
  import java.lang.annotation.*;
  
  /**
   * Indicates that a field/parameter/variable/type parameter/return type may be null.
   */
  @Documented
  @Target(value = {FIELD, METHOD, PARAMETER, LOCAL_VARIABLE, TYPE_PARAMETER, TYPE_USE})
  @Retention(value = CLASS)
  public @interface Nullable { }
  
  