问题
My BlueJ IDE is showing this error when I try to compile the class. I can't see what I'm doing wrong.
回答1:
Before you can use a variable inside your if block , you need to initialize it.
Try this :
double albedo=0;
Instead of :
double albedo;
Keep in mind though that your variable will remain 0 if your condition returns false as you haven't specified an else block.
回答2:
If the condition in the if clause is not true, the variable is not assigned. In this case, the return that follows references an uninitialized variable.
回答3:
This is a private method and local variables don't get default values, they have to be initialized. Consider a case where control doesn't go inside if block, then your variable contains no value, hence the error.
回答4:
Local variables should be initialized with value before using it .Something like this :
double albedo = 0.0;
The compiler complains because local variables are not assigned any value by default. So at run time if the if() condition fails then the variable will not be assigned any value and in that case what value should the run time return back to the caller of the function ? Hence initialize it with some default value.
来源：https://stackoverflow.com/questions/16772394/java-variable-might-not-have-been-initialized