All elements are null problems and solutions appear in java List

All elements are null

You mentioned "List appears All elements are null", which means you have a list and all elements in this list arenull。

If you are using Java

You can check whether a list contains allnullelement:

List<String> list = (null, null, null);  
  
if (().allMatch(Objects::isNull)) {  
    ("All elements are null");  
} else {  
    ("Not all elements are null");  
}

Here we use Java 8's Stream API to check whether all elements in the list arenull。

If you are using Python

You can check this way:

list_data = [None, None, None]  
  
if all(element is None for element in list_data):  
    print("All elements are None")  
else:  
    print("Not all elements are None")

If you encounter such a problem, first of all, you must determine why you get a fullnulllist.

It could be that you did not assign the value correctly when filling this list, or accidentally set all elements tonull。

Summarize

The above is personal experience. I hope you can give you a reference and I hope you can support me more.