public class JavaBean {
    private final String foo;
    private String bar;
    private int qux;
    private Double x,y;

    private JavaBean(Builder builder) {
        foo = builder.foo;
        bar = builder.bar;
        qux = builder.qux;
        x = builder.x;
        y = builder.y;
    }

    public static Builder newJavaBean() {
        return new Builder();
    }

    public static final class Builder {
        private String foo;
        private String bar;
        private int qux;
        private Double x;
        private Double y;

        private Builder() {
        }

        public Builder foo(String val) {
            foo = val;
            return this;
        }

        public Builder bar(String val) {
            bar = val;
            return this;
        }

        public Builder qux(int val) {
            qux = val;
            return this;
        }

        public Builder x(Double val) {
            x = val;
            return this;
        }

        public Builder y(Double val) {
            y = val;
            return this;
        }

        public JavaBean build() {
            return new JavaBean(this);
        }
    }
}