How can we access the array fields from Avro Schema in the Kafka producer code?

I have the below Avro Schema:

    `{
      "name": "ABC",
      "type": "record",
      "namespace": "com.schema.avro",
      "fields": [
        {
          "name": "str1",
          "type": "string"
        },
        {
          "name": "arrData",
          "type":["null",
          {
            "type": "array",
            "items": {
              "name": "arrData_record",
              "type": "record",
              "fields": [
                {
                  "name": "var1",
                  "type": ["null","string"],
                  "default": null
                },
                {
                  "name": "var2",
                  "type": ["null","int"],
                  "default": null
                }
              ]
            }
          }
          ],
          "default": null
        }
      ]
    }`

I used the POM.XML Maven plugin to generate the classes.
Below 2 classes were generated from the plugin-
i) ABC
ii) arrData_record

I am able to use the field str1 from ABC as below:

    ABC abc = ABC.newBuilder()
           .setStr1("random value")
           .build()

Similarly, I am also getting an option to use .setArrData().

I want to set the array fields in a similar way using .setVar1() and .setVar2().

How can I use the fields from the Array class and set it similarly? Any sample code would be of great help.

Thanks.

The generated class from the Avro schema could be manipulated like this

ABC
    .newBuilder()
    .setArrData(Collections.singletonList(arrData_record
        .newBuilder()
        .setVar1("Var1")
        .setVar2(2)
        .build()))
    .build();

Even though I accepted Nic's answer and that answer is correct, I used the below code finally as I wanted to add multiple values in Var1 and Var2-

Populated the objects of the arrData_record using below code-

arrData_record a1 = arrData_record.newBuilder()
.setVar1("abc")
.setVar2(1)
.build();

arrData_record a2 = arrData_record.newBuilder()
.setVar1("def")
.setVar2(2)
.build();

Added it into list arrData-

arrData.add(a1);
arrData.add(a2);

Finally added arrData-

ABC abc = ABC.newBuilder()
.setStr1("random value")
.setarrData(arrData)
.build()