{...

WebElement scriptField =

this.getDriver().findElement(By.cssSelector(".CodeMirror-line>span"));

JavascriptExecutor js = (JavascriptExecutor) this.getDriver();

String query = "text";

js.executeScript("arguments[0].CodeMirror.setValue(""+ query +"");", scriptField);

}

WebElement scriptField = this.getDriver().findElement(By.cssSelector(".CodeMirror-line>span"));
scriptField.sendKeys("your text");

WebElement scriptField = this.getDriver().findElement(By.cssSelector(".CodeMirror-line>span"));
scriptField.clear();
scriptField.sendKeys("your text");