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List<String>- Null


List<String>- Null

By : user3100784
Date : January 12 2021, 09:11 PM
Any of those help I am trying to iterate List from JSON. And everything works fine when List is not null. When is null, i ve got this: Attempt to invoke interface method 'int java.util.List.size()' on a null object reference
code :
Builder allAlsoAvailable = new StringBuilder();
List<String> alsoAvailableList = example.getResult().getAlsoAvailableOn();
if (alsoAvailableList != null) {
  for (int i = 0; i < alsoAvailableList.size(); i++) {
     allAlsoAvailable.append(alsoAvailableList.get(i));
     if (i < alsoAvailableList.size() - 1) allAlsoAvailable.append("\n");
  }
}


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Is list with one String equals (in memory usage) to list with one String and one null object?

Is list with one String equals (in memory usage) to list with one String and one null object?


By : shabina
Date : March 29 2020, 07:55 AM
To fix the issue you can do The initial capacity of an ArrayList is ten (references). That is to say, the underlying array will be of size ten, even if you've only got one entry in your collection. Those references will default to null, and consequently setting the second reference to null will neither affect the internal state of the arraylist (in terms of the underlying array) nor its memory consumption.
If you'd added an eleventh item (set to null), the ArrayList would expand its capacity, and consequently you'd consume more memory, but rather because the ArrayList had created extra buckets for your String references.
How to convert List<string> to List<int> where empty or null string to be converted as 0 using LINQ in C#

How to convert List<string> to List<int> where empty or null string to be converted as 0 using LINQ in C#


By : Prasit Gebsaap
Date : March 29 2020, 07:55 AM
it helps some times How to convert List to List where empty or null string to be converted as 0 using LINQ in C# , Here's my pitch:
code :
        var stringlist = new List<String> { "1", "2", "", null };
        var intList = stringlist.Select(s => { int i; return int.TryParse(s, out i) ? i : 0; }).ToList();
        Debug.Print("{0},{1},{2},{3}", intList[0], intList[1], intList[2], intList[3]);
.Add(null) would break my list<string>. I would like to add in a condition to replcae null with a string

.Add(null) would break my list<string>. I would like to add in a condition to replcae null with a string


By : BringOutTheRain
Date : March 29 2020, 07:55 AM
it should still fix some issue I ran into quite an interesting issue. In conclusion, I learned that empty and null are two different things. , The proper logic would be
code :
    for (int i = 0; i < firstList.Count; i++) {

        // Checks for nulls.
        if(firstList[i] == null){
            _firstList.Add("null");
        }
        else {
            _firstList.Add(firstList[i].ToString());
        } 

        if (secondList[i] == null){
            _secondList.Add("null");
        }
        else{
            _secondList.Add(secondList[i].ToString());
        }
    }
_firstList = firstList.Select(s => s ?? "null").ToList();
_secondList = secondList.Select(s => s ?? "null").ToList();
    for (int i = 0; i < firstList.Count; i++) {
        _firstList.Add(firstList[i]);
        _secondList.Add(secondList[i]);
    }
The constructor TaskLaunchRequest(String, List<String>, null, null) is undefined - Spring Cloud Task

The constructor TaskLaunchRequest(String, List<String>, null, null) is undefined - Spring Cloud Task


By : user1720005
Date : March 29 2020, 07:55 AM
hop of those help? I had the same problem and after the following modifications in the pom file it works.
code :
<spring-cloud.version>Finchley.SR1</spring-cloud.version> 
<spring-cloud.version>Brixton.SR6</spring-cloud.version>
<dependency>
  <groupId>org.springframework.cloud</groupId>
  <artifactId>spring-cloud-starter-task</artifactId>
</dependency> 
<dependency>
  <groupId>org.springframework.cloud</groupId>
  <artifactId>spring-cloud-task-starter</artifactId>
  <version>1.0.1.RELEASE</version>
</dependency>
Future <List <String>> returns null when iterate list of images

Future <List <String>> returns null when iterate list of images


By : user3064623
Date : December 23 2020, 09:01 PM
I think the issue was by ths following , The code that populates the list is asynchronous: imagesToBase64.add(await utils.imageToBase64(imageFile));
But you are returning the list without waiting for the asynchronous computations to finish. Basically, return imagesToBase64; is called before any value is added to it, and is therefore empty. Try something of this sort:
code :
return Future.forEach(_images, (File imageFile) async {
  imagesToBase64.add(await utils.imageToBase64(imageFile));
}).then((_) => imagesToBase64);
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