private long nextId = -1L 是什么意思?
学习是最好的投资!
Declare a private long variable with the variable name nextId, initialize it, and assign the value to -1.
-1L means this is a long型常量
-1L
long型常量
Declare a private long variable with the variable name nextId, initialize it, and assign the value to -1.
-1L
means this is along型常量