How to set Book default page in runtime?

To make a page of book as default in runtime set that PageBackingcontext as active --setActive().

See the code below ,

PageBackingContext pbcHome = null;

PageBackingContext pbcHome1 = null;
PageBackingContext pbcHome2 = null;
PageBackingContext pbcHome3 = null;

BookBackingContext bbc = BookBackingContext.getBookBackingContext(request);
pbcHome = bbc.getPageBackingContextByDefinitionLabel("intranetvz_portal_vzcorp_page");
pbcHome1 = bbc.getPageBackingContextByDefinitionLabel("intranetvz_portal_vso_page");
pbcHome2 = bbc.getPageBackingContextByDefinitionLabel("intranetvz_portal_telebusiness_page");
pbcHome3 = bbc.getPageBackingContextByDefinitionLabel("intranetvz_portal_vzwireless_page");

pbcHome.setActive(false);
pbcHome1.setActive(true); -- Making that page as active
pbcHome2.setActive(false);
pbcHome3.setActive(false);

Thanks,
Venkata Sarvabatla