public class Clazz {
		private Integer firstField;
		private Long secondField;

		@Generated("SparkTools")
		private Clazz(Builder builder) {
			this.firstField = builder.firstField;
			this.secondField = builder.secondField;
		}
		/**
		 * Creates builder to build {@link Clazz}.
		 * @return created builder
		 */
		@Generated("SparkTools")
		public static Builder builder() {
			return new Builder();
		}
		/**
		 * Builder to build {@link Clazz}.
		 */
		@Generated("SparkTools")
		public static class Builder {
			private Integer firstField;
			private Long secondField;

			private Builder() {
			}

			/**
			* Builder method for firstField parameter.
			* @param firstField field to set
			* @return builder
			*/
			@Nonnull
			public Builder withFirstField(@Nonnull Integer firstField) {
				this.firstField = firstField;
				return this;
			}

			/**
			* Builder method for secondField parameter.
			* @param secondField field to set
			* @return builder
			*/
			@Nonnull
			public Builder withSecondField(@Nonnull Long secondField) {
				this.secondField = secondField;
				return this;
			}

			/**
			* Builder method of the builder.
			* @return built class
			*/
			@Nonnull
			public Clazz build() {
				return new Clazz(this);
			}
		}
	}

public class Mail {
	private String from;
	private String to;
	private String subject;
	private String content;
	private String mimeType; // optional

	@Generated("SparkTools")
	private Mail(Builder builder) {
		this.from = builder.from;
		this.to = builder.to;
		this.subject = builder.subject;
		this.content = builder.content;
		this.mimeType = builder.mimeType;
	}

	/**
	 * Creates builder to build {@link Mail}.
	 * 
	 * @return created builder
	 */
	@Generated("SparkTools")
	public static IToStage builder() {
		return new Builder();
	}

	@Generated("SparkTools")
	public interface IToStage {
		public IFromStage withTo(String to);
	}

	@Generated("SparkTools")
	public interface IFromStage {
		public ISubjectStage withFrom(String from);
	}

	@Generated("SparkTools")
	public interface ISubjectStage {
		public IContentStage withSubject(String subject);
	}

	@Generated("SparkTools")
	public interface IContentStage {
		public IBuildStage withContent(String content);
	}

	@Generated("SparkTools")
	public interface IBuildStage {
		public IBuildStage withMimeType(String mimeType);

		public Mail build();
	}

	/**
	 * Builder to build {@link Mail}.
	 */
	@Generated("SparkTools")
	public static final class Builder implements IToStage, IFromStage, ISubjectStage, IContentStage, IBuildStage {
		private String to;
		private String from;
		private String subject;
		private String content;
		private String mimeType;

		private Builder() {
		}

		@Override
		public IFromStage withTo(String to) {
			this.to = to;
			return this;
		}

		@Override
		public ISubjectStage withFrom(String from) {
			this.from = from;
			return this;
		}

		@Override
		public IContentStage withSubject(String subject) {
			this.subject = subject;
			return this;
		}

		@Override
		public IBuildStage withContent(String content) {
			this.content = content;
			return this;
		}

		@Override
		public IBuildStage withMimeType(String mimeType) {
			this.mimeType = mimeType;
			return this;
		}

		@Override
		public Mail build() {
			return new Mail(this);
		}
	}

}