关于java字符串“hello”和“hello”的问题

Question

Why this is invalid in java?

List<String> items=new ArrayList<String>();
items.add("hello"); // valid
items.add('hello'); // invalid (error: invalid character constants)

Answer 1

Because '' single quotes are used for char variables. Meaning 'a' , 'b' , and so on. So only one character per variable.

The double quotes on the other side "" are used to initialize String variables, which are several characters gathered together into one variable eg "i am a string"

char c = 'c' // I use single quotes because I am single :)
String str = "This is a string" // I use double quotes because I got a lot in me