Reports any cases in which java.util.Optional<T>, java.util.OptionalDouble, java.util.OptionalInt, java.util.OptionalLong, or com.google.common.base.Optional are used as types for fields or parameters.

Optional was designed to provide a limited mechanism for library method return types in which a clear way to represent "no result" was needed.

Using a field with the java.util.Optional type is also problematic if the class needs to be Serializable, as java.util.Optional is not serializable.

Example:


  class MyClass {
    Optional<String> name; // Optional field

    // Optional parameter
    void setName(Optional<String> name) {
      this.name = name;
    }
  }

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