Custom Script Field to sum value those results comes in billion

[Amit Kumar Singh]

What should is use in place of double to calculate the value in billion.

import com.atlassian.jira.component.ComponentAccessor

import com.atlassian.jira.issue.history.ChangeItemBean

// Get values from 4 custom fields

Double val1 = makeNullZero(getCustomFieldValue('Field Name ($)'));

Double val1 = makeNullZero(getCustomFieldValue('Field Name ($)'));

Double val1 = makeNullZero(getCustomFieldValue('Field Name ($)'));

Double val1 = makeNullZero(getCustomFieldValue('Field Name ($)'));

Double sum = val1 + val2 + val3 + val4;

return sum;

static Double makeNullZero(Double val) {

    return null == val ? 0 : val;

}