China will become the worlds largest economy then, since Chinas largest trading partner is Europe, and 2nd largest is America.
If America goes bankrupt, they will have to pay China and Japan back the money owed. So if America declared backrupcy, then this will allow China to take Alaska, Guam, Hawaii as their own and any government infrastructure which equals 1.5trillion dollars.
They new currency will quickly be converter to Euros or Sterling and don't forget that China actually has the money to keep their economy growing. China will just unleash trillions of dollars of government reserves to keep their country spending money to keep growing and Europe will only have the option to sell/buy from China.
Japan would still stay alive considering China is Japans largest trading partner and vice-versa but America sure as hell would plunge into massive recession leaving millions and millions of American citizens homeless.
The fact is this. Any country who has America as their largest trading partner will collapse immediately, with other countries feeling the effect and stress of it.
But as for China, Japan, Europe and any other country who doesn't have to rely on America, well, they will find their way out of it by either creating a monetary fund to bail out America just like Europe had to bail out Greece.
Canada, Mexico, Germany, Israel and any country who relys on America for export will immediately plunge into recession.
Since China is the driving force of the global economy since accession during the WTO and the 2008 recession, China wouldn't be affected if Canada, Mexico, or Israel were wiped from the economy since China has minimal trade with those countries.
As long as Europe (Chinas largest trading partner) and Japan doesn't go bankrupt, China will still grow rapidly but America is Chinas 2nd largest trading partner, so China will obviously feel the effect but they have the money to shield it from any recession. China is already sitting on 3.5 trillion dollars in reserves alone!!! China has one of the highest bank reserve ratios in the world at over 15%.
So in the case that this does happen, America will be split, since China and Japan are Americas largest debt funders, this would mean China would get Alaska and alot of land, while Japan would get some land and billions of dollars worth of buildings to recoup their losses.
Remember that what you borrow, you must pay back. Just like if you go bankrupt, the bank will take your home and anything and everything you own, until it's fully paid back.
Just to prove any theory out there. During the 2008 recession, Americas GDP fell over 10%, while Chinas GDP increased over 12%.
That just proved that even with Americans falling into recession with people and markets panicing, China still had an astounding double digit growth of over 10+ for the past 4 years.
At the end of the day, it really depends on how much resources a country has, such as money to play around with. Greece was bankrupt and didn't have a cent to pump back into the economy, where as, China is sitting on a HUGE amount of reserves worth trillions and trillions of dollars and also has even more tucked away in the government social spending bank which is only used for emergencies.
Europe also already has a bailout fund which has over 500billion dollars in it and is expected to have over 750bil by the end of 2014.
America, however, doesn't even have a penny! They only rely on the FedReserve to pump the money by printing more and more, which causes inflation which makes the money worthless if they do try it that way. Americas debt is already at over 15.5tril.