Please make a separate thread for this. Very interesting topic and will be a learning experience for many.
It's not interesting per se, it is basically their economy is in permanent "stimulus" mode.
As you know they are a "command economy" aside from the capitalist export economy bits.
Which means they have many PSUs for every industrial/construction segment you can imagine.
Now most Governments when doing "stimulus" give out large infrastructure contracts basically.
In China's context this is building new cities, new highways, new railway tracks both HSR and the normal ones, new ports and expansion/maintenance of existing ones, new support infrastructure for cities like sewage lines, water supply, power supply, internet, what have you.
Then there is this fully indigenized MIC, an MIC itself is a very expansive web of specialty subcomponents in building some military product as you may be aware.
There are many more subsegments i'm missing, but hopefully the point has been put across.
Now in all the types mentioned above CCP has all kinds of PSUs involved, and like our ones they hire more people than is necessary, now for Infrastructure aside from the labour involved, you also need to buy raw materials, subcomponents, assemblies and "products" like say rolling stock for your railway tracks right? fear not, you will purchase all these from other Chinese PSUs, and a smattering of large and small private companies also.
More orders means more money for everyone involved, for state controlled PSUs this is a "circular system" for private players these mean more money to invest, add more capacity, and expand business to supplying for domestic market or exports.
Now there are also the employees working in the companies in this web of procurement, construction, manufacturing, engineering, design etc, all who have salaries, all who will spend this money.
This is how you get inflated GDP growth rate % there.
You may be wondering now, where does all this limitless money come from, for all these excesses, like unnecessary cities, infrastructure development, production of commodities and manufactured products, since these all are state led?
Most of this is jhol money, it will be an IL&FS crisis when this all comes out in the open, but the current system is a "win-win" for everyone involved, and it is beneficial that it continues, but they also perhaps take copious loans from global lending organizations, and they also have bought US govt "bonds", I guess that is a source of funding too.
Forgive me but my knowledge on the topic of "Where do the CCP get their money from" is a bit patchy, so someone with economics/banking background can post a clearer picture.