Parsing of thread safe classes: (2.8-3.6)

Thread safe classes are generally embodied in the process of multithreading concurrency , There are mainly five kinds of : immutable , Absolutely safe class , Relatively safe classes , Thread compatibility , Thread opposition ;

immutable :
By final Modified class ;
String Type of ;
Enumeration type , Such as : public Enum Color{RED,GREEN};
Floating point references wrap exact types and large values : BigInteger,BigDecimal;

Absolutely safe class :
Is to add... Again on the relatively safe class synchronized keyword , such as vector Add it to the front and it becomes an absolutely safe class ;

Relatively safe classes :
vector and hashtable When you have a layer of synchronized Class ;

Thread compatibility :
image ArrayList and HashMap Itself is not safe , It can be preceded by synchronized You can synchronize secure classes ;

Thread opposition :
thread The following two classes suspend and resume, Has now been abandoned , Like threads A Hold lock C perform suspend After suspending the operation , Threads B Lock required C can resume Wake up the way , Wake up the
Threads A; The thread B Will always be in a waiting state, forming a deadlock , So he was abandoned ;