Understand the execution sequence of try catch finally in one diagram

What is? try-catch-finally

yes java Is used to catch exceptions , And handle exceptional blocks .

1. try In the block are the codes that may cause exceptions
2. catch The possible exceptions are placed in the block
3. finally The block contains code that must be executed

Understand the execution sequence with a picture

Use scenarios ( Database operation as an example )

When accessing a database , An error may occur during execution , At this point through try-catch Block for processing

DataBase db;
try {
    
	User user = db.getUser();
	return user;
} catch (DBException e) {
    
	e.printStack();
	return null;
} finally {
    
	db.close();
}

Detailed conclusion

1. finally There is... In the block return sentence , Returns the finally Medium return Value
2. No matter what catch Block or try Whether there is in the block return sentence ,finally The statement in must execute
3. finally in return When the sentence is , The compiler will warn , But there is no error .