Mfcttrf

What is the difference between x RadToDeg cos x div and COSC?

How did researchers use to find articles before the Internet and the computer era?

Should I report a leak of confidential HR information?

How to expand abbrevs without hitting another extra key?

Can I ask to speak to my future colleagues before accepting an offer?

Needle Hotend for nonplanar printing

How can I convince my reader that I will not use a certain trope?

Most elegant way to write a one shot IF

What are good ways to spray paint a QR code on a footpath?

What is the line crossing the Pacific Ocean that is shown on maps?

What is "oversubscription" in Networking?

Meaning of もてり and use of が

Can the passive "être + verbe" sometimes mean the past?

In the context of a differentiator circuit, what is a “current-sensing resistor”?

In native German words, is Q always followed by U, as in English?

Convergenge or divergence of series with e

Why are 120 V general receptacle circuits limited to 20 A?

Is there reliable evidence that depleted uranium from the 1999 NATO bombing is causing cancer in Serbia?

Sum of Parts of An Array - JavaScript

How exactly is a normal force exerted, at the molecular level?

Why won't the ground take my seed?

Acceleration in Circular motion

Can 'leave' mean 'forget'?

Miss Toad and her frogs

Attempt to de-reference a null object: list initialization

JSON.DeserializeUntyped: Can I infer anything from the Object returned?Map of attachment insertionschema.getglobaldescribe needs test classCode Coverage to Test Custom Object Public Listfault string: No such parameter param defined for the operation, please check the WSDL for the serviceAttempt to de-reference a null object - Error in sorting listAPEX: Attempt to de-reference a null objectTry/Catch for Attempt to Dereference Null ObjectDisplaying map in Visualforce - key with List<List<>> valueshow to display picklist values which is stored in custom settings values based on the condition

.everyoneloves__top-leaderboard:empty,.everyoneloves__mid-leaderboard:empty,.everyoneloves__bot-mid-leaderboard:empty margin-bottom:0;

3

I initialize the list at the beginning of the code. In one of the methods, I add values ​​to it. In another method, the list is already empty. But I need these values ​​in the second method. How to save them to get after?

public static List<String> listsIds = new List<String>();

@AuraEnabled
public static List<Object> getLists()
//If I initialize the list here, nothing will change: "listsIds" will be null

 Http http = new Http();
 HttpRequest request = new HttpRequest();
 request.setEndpoint('myEndpointIsHere');
 request.setMethod('GET'); 
 HttpResponse response = http.send(request);

 Map<String, Object> results = (Map<String, Object>) JSON.deserializeUntyped(response.getBody());
 List<Object> lists = (List<Object>) results.get('lists');
 List<String> listsNames = new List<String>();

 for(Object oneList : lists)
 String listInText = String.valueOf(oneList);
 String listName = listInText.substringBetween('name=', '');
 String listId = listInText.substringBetween('id=', ',');
 listsNames.add(listName);
 //Here I added the values:
 listsIds.add(listId);
 
 return listsNames;
}

@AuraEnabled
public static void testIt()
 //Empty List:
 System.debug(listsIds);

apex error list null

share|improve this question

edited 8 hours ago

MichaelLev19

asked 8 hours ago

MichaelLev19MichaelLev19

13088 bronze badges

add a comment | 

3

I initialize the list at the beginning of the code. In one of the methods, I add values ​​to it. In another method, the list is already empty. But I need these values ​​in the second method. How to save them to get after?

public static List<String> listsIds = new List<String>();

@AuraEnabled
public static List<Object> getLists()
//If I initialize the list here, nothing will change: "listsIds" will be null

 Http http = new Http();
 HttpRequest request = new HttpRequest();
 request.setEndpoint('myEndpointIsHere');
 request.setMethod('GET'); 
 HttpResponse response = http.send(request);

 Map<String, Object> results = (Map<String, Object>) JSON.deserializeUntyped(response.getBody());
 List<Object> lists = (List<Object>) results.get('lists');
 List<String> listsNames = new List<String>();

 for(Object oneList : lists)
 String listInText = String.valueOf(oneList);
 String listName = listInText.substringBetween('name=', '');
 String listId = listInText.substringBetween('id=', ',');
 listsNames.add(listName);
 //Here I added the values:
 listsIds.add(listId);
 
 return listsNames;
}

@AuraEnabled
public static void testIt()
 //Empty List:
 System.debug(listsIds);

apex error list null

share|improve this question

edited 8 hours ago

MichaelLev19

asked 8 hours ago

MichaelLev19MichaelLev19

13088 bronze badges

add a comment | 

I initialize the list at the beginning of the code. In one of the methods, I add values ​​to it. In another method, the list is already empty. But I need these values ​​in the second method. How to save them to get after?

public static List<String> listsIds = new List<String>();

@AuraEnabled
public static List<Object> getLists()
//If I initialize the list here, nothing will change: "listsIds" will be null

 Http http = new Http();
 HttpRequest request = new HttpRequest();
 request.setEndpoint('myEndpointIsHere');
 request.setMethod('GET'); 
 HttpResponse response = http.send(request);

 Map<String, Object> results = (Map<String, Object>) JSON.deserializeUntyped(response.getBody());
 List<Object> lists = (List<Object>) results.get('lists');
 List<String> listsNames = new List<String>();

 for(Object oneList : lists)
 String listInText = String.valueOf(oneList);
 String listName = listInText.substringBetween('name=', '');
 String listId = listInText.substringBetween('id=', ',');
 listsNames.add(listName);
 //Here I added the values:
 listsIds.add(listId);
 
 return listsNames;
}

@AuraEnabled
public static void testIt()
 //Empty List:
 System.debug(listsIds);

apex error list null

share|improve this question

edited 8 hours ago

MichaelLev19

asked 8 hours ago

MichaelLev19MichaelLev19

13088 bronze badges

public static List<String> listsIds = new List<String>();

@AuraEnabled
public static List<Object> getLists()
//If I initialize the list here, nothing will change: "listsIds" will be null

 Http http = new Http();
 HttpRequest request = new HttpRequest();
 request.setEndpoint('myEndpointIsHere');
 request.setMethod('GET'); 
 HttpResponse response = http.send(request);

 Map<String, Object> results = (Map<String, Object>) JSON.deserializeUntyped(response.getBody());
 List<Object> lists = (List<Object>) results.get('lists');
 List<String> listsNames = new List<String>();

 for(Object oneList : lists)
 String listInText = String.valueOf(oneList);
 String listName = listInText.substringBetween('name=', '');
 String listId = listInText.substringBetween('id=', ',');
 listsNames.add(listName);
 //Here I added the values:
 listsIds.add(listId);
 
 return listsNames;
}

@AuraEnabled
public static void testIt()
 //Empty List:
 System.debug(listsIds);

share|improve this question

edited 8 hours ago

MichaelLev19

asked 8 hours ago

MichaelLev19MichaelLev19

13088 bronze badges

share|improve this question

edited 8 hours ago

MichaelLev19

asked 8 hours ago

MichaelLev19MichaelLev19

13088 bronze badges

asked 8 hours ago

MichaelLev19MichaelLev19

13088 bronze badges

asked 8 hours ago

MichaelLev19MichaelLev19

13088 bronze badges

1 Answer
1

active

oldest

votes

6

static methods share state (in the form of static variables) only in the context of a single transaction. Each Lightning server call to an @AuraEnabled method takes place in a separate transaction; no state is stored on the server across such invocations. Each such method will start with the same value for listIds, which is an empty list - your initializer will be run anew on each invocation.

Your state needs to be stored on the client, in attributes of your Lightning component. Your client-side controller can then pass needed state to your Apex methods as a parameter. You will not be able to store it on the server in this way unless you choose to persist it as an object, which will add a lot of complexity and is likely something you'd want to do only if the data is large, long-lived, and expensive to compute.

share|improve this answer

edited 8 hours ago

answered 8 hours ago

David Reed♦David Reed

45.6k88 gold badges2626 silver badges6565 bronze badges

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  Beat me to it :)
  
  – gNerb
  8 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Thank you :))))
  
  – MichaelLev19
  8 hours ago
  

  
  
  
  

add a comment | 

Your Answer

StackExchange.ready(function()
var channelOptions =
tags: "".split(" "),
id: "459"
;
initTagRenderer("".split(" "), "".split(" "), channelOptions);

StackExchange.using("externalEditor", function()
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled)
StackExchange.using("snippets", function()
createEditor();
);

else
createEditor();

);

function createEditor()
StackExchange.prepareEditor(
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: false,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: null,
bindNavPrevention: true,
postfix: "",
imageUploader:
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
,
onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
);



);

draft saved

draft discarded

Sign up or log in

StackExchange.ready(function ()
StackExchange.helpers.onClickDraftSave('#login-link');
);

Sign up using Google

Sign up using Facebook

Sign up using Email and Password

Post as a guest

Name

Email

Required, but never shown

StackExchange.ready(
function ()
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fsalesforce.stackexchange.com%2fquestions%2f267059%2fattempt-to-de-reference-a-null-object-list-initialization%23new-answer', 'question_page');

);

Post as a guest

Name

Email

Required, but never shown

6

static methods share state (in the form of static variables) only in the context of a single transaction. Each Lightning server call to an @AuraEnabled method takes place in a separate transaction; no state is stored on the server across such invocations. Each such method will start with the same value for listIds, which is an empty list - your initializer will be run anew on each invocation.

Your state needs to be stored on the client, in attributes of your Lightning component. Your client-side controller can then pass needed state to your Apex methods as a parameter. You will not be able to store it on the server in this way unless you choose to persist it as an object, which will add a lot of complexity and is likely something you'd want to do only if the data is large, long-lived, and expensive to compute.

share|improve this answer

edited 8 hours ago

answered 8 hours ago

David Reed♦David Reed

45.6k88 gold badges2626 silver badges6565 bronze badges

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  Beat me to it :)
  
  – gNerb
  8 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Thank you :))))
  
  – MichaelLev19
  8 hours ago
  

  
  
  
  

add a comment | 

6

static methods share state (in the form of static variables) only in the context of a single transaction. Each Lightning server call to an @AuraEnabled method takes place in a separate transaction; no state is stored on the server across such invocations. Each such method will start with the same value for listIds, which is an empty list - your initializer will be run anew on each invocation.

Your state needs to be stored on the client, in attributes of your Lightning component. Your client-side controller can then pass needed state to your Apex methods as a parameter. You will not be able to store it on the server in this way unless you choose to persist it as an object, which will add a lot of complexity and is likely something you'd want to do only if the data is large, long-lived, and expensive to compute.

share|improve this answer

edited 8 hours ago

answered 8 hours ago

David Reed♦David Reed

45.6k88 gold badges2626 silver badges6565 bronze badges

• 
  
  
  

  
  1
  

  
  
  
  
  
  

  
  
  Beat me to it :)
  
  – gNerb
  8 hours ago
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Thank you :))))
  
  – MichaelLev19
  8 hours ago
  

  
  
  
  

add a comment | 

static methods share state (in the form of static variables) only in the context of a single transaction. Each Lightning server call to an @AuraEnabled method takes place in a separate transaction; no state is stored on the server across such invocations. Each such method will start with the same value for listIds, which is an empty list - your initializer will be run anew on each invocation.

Your state needs to be stored on the client, in attributes of your Lightning component. Your client-side controller can then pass needed state to your Apex methods as a parameter. You will not be able to store it on the server in this way unless you choose to persist it as an object, which will add a lot of complexity and is likely something you'd want to do only if the data is large, long-lived, and expensive to compute.

share|improve this answer

edited 8 hours ago

answered 8 hours ago

David Reed♦David Reed

45.6k88 gold badges2626 silver badges6565 bronze badges

share|improve this answer

edited 8 hours ago

answered 8 hours ago

David Reed♦David Reed

45.6k88 gold badges2626 silver badges6565 bronze badges

answered 8 hours ago

David Reed♦David Reed

45.6k88 gold badges2626 silver badges6565 bronze badges

answered 8 hours ago

David Reed♦David Reed

45.6k88 gold badges2626 silver badges6565 bronze badges