public class ImBase {
    protected ImBase(Builder b) {
    }

    public static class Builder<B extends Builder> {
        protected final BuilderHolder<B> holder;

        public Builder() {
            this.holder = new BuilderHolder(this);
        }

        public B setFoo(String value) {
            return holder.b;
        }

        public B setBar(int value) {
            return holder.b;
        }

        public ImBase build() {
            return new ImBase(holder.b);

        }
        protected static class BuilderHolder<T extends Builder> {
            public final T b;

            private BuilderHolder(T b) {
                this.b = b;
            }
        }
    }
}

public class ImBaseChild extends ImBase {
    protected ImBaseChild(Builder b) {
        super(b);
    }

    public static class Builder extends ImBase.Builder<Builder> {
        public Builder setGer(double value) {
            return holder.b;
        }

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

public class ImMain {
    public static void main(String[] args) {
        ImBase imBase = new ImBase.Builder().setBar(1).setFoo("22").build();
        ImBaseChild imBaseChild1 = new ImBaseChild.Builder().setGer(3.3).setBar(1).setFoo("22").build();
    }
}