[SalesForce] Static method cannot be referenced from a non static context: List

I believe this is a basic query and am missing something out.
However am exasperated finding an answer to the issue and thus seek your guidance.

The intent is to create a static method generateStringArray() that can return an array. However whenever I run the code in the below form, it throws error:

Static method cannot be referenced from a non static context: List<String>

My method is static and arrays can be returned from static
Instead of string, if I use void and don't return, the compiler does run

Why is this throwing an error?
What part of the code is being run as a class instance and not static?
Does it have soemthing to do with the way I have defined the function or the string ?

I have checked at other solutions available for the similar issue but my query pertains to what is not static in the code?

Code

public class test_clonestring {

    public static String[] generateStringArray (Integer lenstr){    
        String[] sstring = new String[lenstr]; 

        for (Integer i = 0; i<lenstr; i++) {
            sstring[i] = 'Test ' + i;
        }            

        system.debug('STD_DBG:0:'+sstring);

        return (sstring);

    }
}

Best Answer

The code you have posted does compile. To call it you will need to use the class name like this (because the method is static):

String[] stringArray = test_clonestring.generateStringArray(5);

This will not compile:

String[] stringArray = new test_clonestring().generateStringArray(5);

Related Solutions

[SalesForce] Simple Apex class to return a list of strings

You can't instantiate a List like that using an integer. You don't need to explicitly specify how much items are going into the list when it is created. Instead, just remove the integer:

//Instantiate the list
String[] myArray = new List<String>();

You're logic in your loop seems to be incorrect as well. Specifically, myArray's size will always be 0 when you instantiate it. Change your loop logic to:

for(Integer i=0;i<length;i++) {
   // code
}

You want to generate a List of strings based on the i variable. You will want to change your internal logic to:

//Populate the array
myArray.add('Test ' + i);

// Write value to the debug log
System.debug(myArray[i]);

Finally, you want to return that Array. You need to change your method so the return type is no longer void by changing its signature:

public static String[] generateStringArray(Integer length)

then it is just a matter of returning that array at the end of your method:

return myArray;

This would bring it all together as:

public class StringArrayTest {
    //Public Method
    public static String[] generateStringArray(Integer length) {
        //Instantiate the list
        String[] myArray = new List<String>();

        //Iterate throught the list
        for(Integer i=0;i<length;i++) {
            //Populate the array
            myArray.add('Test ' + i);

            // Write value to the debug log
            System.debug(myArray[i]);
        } //end loop

        return myArray;
    }//end method       
}// end class

Some more info on Arrays and Lists, Loops, and Class methods for future reference.

[SalesForce] Cannot Return a List of Strings – Void method must not return a value

You declared your return type as void. Change it to List<String>.

Incorrect

public static void generateStringArray

Correct

public static List<String> generateStringArray

It would be worth your time to read up on Class Methods:

To define a method, specify the following:

Optional: Modifiers, such as public or protected.

Required: The data type of the value returned by the method, such as String or Integer. Use void if the method does not return a value.

Required: A list of input parameters for the method, separated by commas, each preceded by its data type, and enclosed in parentheses (). If there are no parameters, use a set of empty parentheses. A method can only have 32 input parameters.

Required: The body of the method, enclosed in braces {}. All the code for the method, including any local variable declarations, is contained here. Use the following syntax when defining a method:
[public | private | protected | global] [override] [static] data_type method_name 
(input parameters) 
{
// The body of the method
}

It is your data_type that you have incorrectly specified as void in this case.

Best Answer

Related Solutions

[SalesForce] Simple Apex class to return a list of strings

[SalesForce] Cannot Return a List of Strings – Void method must not return a value

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