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David Lee 8David Lee 8 

JSONGenerator and JSONParser do not work

I am trying to generate and parse JSON, but JSONGenerator and JSONParser do not seem to work. Execution stops without any errors.

for example, run the following code in the console:
  
List<Contact> contacts = [SELECT Id, Name FROM Contact LIMIT 10]; 
System.debug(1);
JSONGenerator generator = JSON.createGenerator(true);
System.debug(2);
generator.writeStartObject();
generator.writeNumberField('count', contacts.size())
generator.writeEndObject();
String jsonString = generator.getAsString();
System.debug(jsonString);
All I get is USER_DEBUG [14]|DEBUG|1. There are no errors in the output. Same happens when I try to use JSONParser.
 
Magesh Mani YadavMagesh Mani Yadav
HI David,
Try this. Should work 
List<Contact> contacts = [SELECT Id, Name FROM Contact LIMIT 10]; 
System.debug(1);
JSONGenerator generator = JSON.createGenerator(true);
System.debug(2);
generator.writeStartObject();
generator.writeNumberField('count', contacts.size());
generator.writeEndObject();
String jsonString = generator.getAsString();
System.debug('jsonString: '+jsonString);


 
David Lee 8David Lee 8
Thanks, but I'm getting the same thing: USER_DEBUG [14]|DEBUG|1 And then execution just stops.
Magesh Mani YadavMagesh Mani Yadav
For me its woking. see the log 
37.0 APEX_CODE,FINEST;APEX_PROFILING,INFO;CALLOUT,INFO;DB,INFO;SYSTEM,DEBUG;VALIDATION,INFO;VISUALFORCE,INFO;WORKFLOW,INFO
Execute Anonymous: List<Contact> contacts = [SELECT Id, Name FROM Contact LIMIT 10]; 
Execute Anonymous: System.debug(1);
Execute Anonymous: JSONGenerator generator = JSON.createGenerator(true);
Execute Anonymous: System.debug(2);
Execute Anonymous: generator.writeStartObject();
Execute Anonymous: generator.writeNumberField('count', contacts.size());
Execute Anonymous: generator.writeEndObject();
Execute Anonymous: String jsonString = generator.getAsString();
Execute Anonymous: System.debug('jsonString: '+jsonString);

15:55:57.3 (3576817)|EXECUTION_STARTED
15:55:57.3 (3581091)|CODE_UNIT_STARTED|[EXTERNAL]|execute_anonymous_apex
15:55:57.3 (3871905)|VARIABLE_SCOPE_BEGIN|[1]|contacts|List<Contact>|true|false
15:55:57.3 (3939959)|VARIABLE_SCOPE_BEGIN|[3]|generator|System.JSONGenerator|true|false
15:55:57.3 (3963990)|VARIABLE_SCOPE_BEGIN|[8]|jsonString|String|false|false
15:55:57.3 (4110423)|HEAP_ALLOCATE|[72]|Bytes:3
15:55:57.3 (4163553)|HEAP_ALLOCATE|[77]|Bytes:152
15:55:57.3 (4182240)|HEAP_ALLOCATE|[342]|Bytes:408
15:55:57.3 (4200987)|HEAP_ALLOCATE|[355]|Bytes:408
15:55:57.3 (4218622)|HEAP_ALLOCATE|[467]|Bytes:48
15:55:57.3 (4261996)|HEAP_ALLOCATE|[139]|Bytes:6
15:55:57.3 (4291592)|HEAP_ALLOCATE|[EXTERNAL]|Bytes:17
15:55:57.3 (4463793)|STATEMENT_EXECUTE|[1]
15:55:57.3 (4467154)|STATEMENT_EXECUTE|[1]
15:55:57.3 (4471876)|HEAP_ALLOCATE|[1]|Bytes:37
15:55:57.3 (4485854)|HEAP_ALLOCATE|[1]|Bytes:4
15:55:57.3 (4533439)|HEAP_ALLOCATE|[50]|Bytes:5
15:55:57.3 (4560813)|HEAP_ALLOCATE|[56]|Bytes:5
15:55:57.3 (4571132)|HEAP_ALLOCATE|[64]|Bytes:7
15:55:57.3 (4808081)|SOQL_EXECUTE_BEGIN|[1]|Aggregations:0|SELECT Id, Name FROM Contact LIMIT 10
15:55:57.3 (16328398)|SOQL_EXECUTE_END|[1]|Rows:10
15:55:57.3 (16370589)|HEAP_ALLOCATE|[1]|Bytes:44
15:55:57.3 (16405300)|HEAP_ALLOCATE|[1]|Bytes:482
15:55:57.3 (16471210)|HEAP_ALLOCATE|[1]|Bytes:44
15:55:57.3 (16573998)|VARIABLE_ASSIGNMENT|[1]|contacts|{"s":1,"v":"List of size 10 too large to display"}|0x659ee34a
15:55:57.3 (16581759)|STATEMENT_EXECUTE|[2]
15:55:57.3 (16688191)|USER_DEBUG|[2]|DEBUG|1
15:55:57.3 (16714562)|STATEMENT_EXECUTE|[3]
15:55:57.3 (16787025)|SYSTEM_MODE_ENTER|false
15:55:57.3 (16830081)|HEAP_ALLOCATE|[3]|Bytes:5
15:55:57.3 (16922176)|HEAP_ALLOCATE|[3]|Bytes:24
15:55:57.3 (16945204)|SYSTEM_METHOD_ENTRY|[1]|JSON.JSON()
15:55:57.3 (16949217)|STATEMENT_EXECUTE|[1]
15:55:57.3 (16964027)|SYSTEM_METHOD_EXIT|[1]|JSON
15:55:57.3 (16987511)|METHOD_ENTRY|[3]||System.JSON.createGenerator(Boolean)
15:55:57.3 (17213905)|METHOD_EXIT|[3]||System.JSON.createGenerator(Boolean)
15:55:57.3 (17225995)|SYSTEM_MODE_EXIT|false
15:55:57.3 (17283165)|VARIABLE_ASSIGNMENT|[3]|generator|{"delegate":"0x689afdca"}|0x6d6cf6df
15:55:57.3 (17289080)|STATEMENT_EXECUTE|[4]
15:55:57.3 (17323339)|USER_DEBUG|[4]|DEBUG|2
15:55:57.3 (17332056)|STATEMENT_EXECUTE|[5]
15:55:57.3 (17367159)|SYSTEM_MODE_ENTER|false
15:55:57.3 (17385105)|HEAP_ALLOCATE|[5]|Bytes:5
15:55:57.3 (17419878)|METHOD_ENTRY|[5]||System.JSONGenerator.writeStartObject()
15:55:57.3 (17476900)|METHOD_EXIT|[5]||System.JSONGenerator.writeStartObject()
15:55:57.3 (17483710)|SYSTEM_MODE_EXIT|false
15:55:57.3 (17489625)|STATEMENT_EXECUTE|[6]
15:55:57.3 (17497217)|HEAP_ALLOCATE|[6]|Bytes:5
15:55:57.3 (17630176)|SYSTEM_MODE_ENTER|false
15:55:57.3 (17647850)|HEAP_ALLOCATE|[6]|Bytes:5
15:55:57.3 (17675833)|METHOD_ENTRY|[6]||System.JSONGenerator.writeNumberField(String, Integer)
15:55:57.3 (17759855)|METHOD_EXIT|[6]||System.JSONGenerator.writeNumberField(String, Integer)
15:55:57.3 (17773068)|SYSTEM_MODE_EXIT|false
15:55:57.3 (17782624)|STATEMENT_EXECUTE|[7]
15:55:57.3 (17819487)|SYSTEM_MODE_ENTER|false
15:55:57.3 (17847720)|HEAP_ALLOCATE|[7]|Bytes:5
15:55:57.3 (17863347)|METHOD_ENTRY|[7]||System.JSONGenerator.writeEndObject()
15:55:57.3 (17905570)|METHOD_EXIT|[7]||System.JSONGenerator.writeEndObject()
15:55:57.3 (17912042)|SYSTEM_MODE_EXIT|false
15:55:57.3 (17917614)|STATEMENT_EXECUTE|[8]
15:55:57.3 (17947036)|SYSTEM_MODE_ENTER|false
15:55:57.3 (17963621)|HEAP_ALLOCATE|[8]|Bytes:5
15:55:57.3 (17977339)|METHOD_ENTRY|[8]||System.JSONGenerator.getAsString()
15:55:57.3 (18025116)|METHOD_EXIT|[8]||System.JSONGenerator.getAsString()
15:55:57.3 (18033027)|SYSTEM_MODE_EXIT|false
15:55:57.3 (18058435)|VARIABLE_ASSIGNMENT|[8]|jsonString|"{\n  \"count\" : 10\n}"
15:55:57.3 (18062706)|STATEMENT_EXECUTE|[9]
15:55:57.3 (18068031)|HEAP_ALLOCATE|[9]|Bytes:12
15:55:57.3 (18094783)|HEAP_ALLOCATE|[9]|Bytes:30
15:55:57.3 (18123165)|USER_DEBUG|[9]|DEBUG|jsonString: {
  "count" : 10
}
15:55:57.18 (18187021)|CUMULATIVE_LIMIT_USAGE
15:55:57.18 (18187021)|LIMIT_USAGE_FOR_NS|(default)|
  Number of SOQL queries: 1 out of 100
  Number of query rows: 10 out of 50000
  Number of SOSL queries: 0 out of 20
  Number of DML statements: 0 out of 150
  Number of DML rows: 0 out of 10000
  Maximum CPU time: 0 out of 10000
  Maximum heap size: 0 out of 6000000
  Number of callouts: 0 out of 100
  Number of Email Invocations: 0 out of 10
  Number of future calls: 0 out of 50
  Number of queueable jobs added to the queue: 0 out of 50
  Number of Mobile Apex push calls: 0 out of 10

15:55:57.18 (18187021)|CUMULATIVE_LIMIT_USAGE_END

15:55:57.3 (18236374)|CODE_UNIT_FINISHED|execute_anonymous_apex
15:55:57.3 (20429513)|EXECUTION_FINISHED

 
David Lee 8David Lee 8
Is there a package I need to install or something like that? JSON is a part of System namespace, so I expect it to be avaialable by default.
Magesh Mani YadavMagesh Mani Yadav
Yes it available by default.
Did you really try the code which I shared because in your code you were missing some syntax.
David Lee 8David Lee 8
Yes, I pasted the whole thing.
Magesh Mani YadavMagesh Mani Yadav
can you share that console code again?
David Lee 8David Lee 8
I just noticed that my debug levels were messed up, that's why the messages did not show up. Thanks for your help!
Srikanth Kolanu 18Srikanth Kolanu 18
Check this site for basic program

http://salesforcecodes.com/related-contacts-display-for-account-using-jsongenerator/