Create custom appender for output log messages to text area with spring boot

I can't create instance of my class because a don't know how to pass needed parameters in createAppender method from log4j.xml.

Exception:

Parameter 0 of constructor in ru.appliedtech.desktopapp.client.ui.menu.JTextAreaAppender required a bean of type 'java.lang.String' that could not be found. Consider defining a bean of type 'java.lang.String' in your configuration.

@Plugin(name = "JTextAreaAppender", category = "Core", elementType = "appender", printObject = true)
@Configuration
@ComponentScan("ru.appliedtech")
public class JTextAreaAppender extends AbstractAppender
{
    private int maxLines = 0;
    private static volatile ArrayList<JTextArea> jTextAreaList = new ArrayList<>();

    protected JTextAreaAppender(String name, Filter filter, Layout<? extends Serializable> layout, boolean ignoreExceptions, Property[] properties)
    {
        super(name, filter, layout, ignoreExceptions, properties);
    }

    @PluginFactory
    public static JTextAreaAppender createAppender(@PluginAttribute("name") String name,
                                                   @PluginAttribute("ignoreExceptions") boolean ignoreExceptions,
                                                   @PluginElement("Layout") Layout<?> layout,
                                                   @PluginElement("Filters") Filter filter,
                                                   @PluginElement("Properties") Property[] properties) {
        return new JTextAreaAppender(name, filter, layout, ignoreExceptions, properties);
    }

    /**
     * add the target JTextArea to be populated and updated by the logging information
     * @param textArea text area
     */
    public static void addTextArea(final JTextArea textArea) {
        JTextAreaAppender.jTextAreaList.add(textArea);
    }

    @Override
    public void append(LogEvent event)
    {
        //
    }
}

log4j.xml

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="ERROR" packages="ru.appliedtech.desktopapp.client.ui.menu">
    <Properties>
        <Property name="APP_LOG_ROOT">ru.appliedtech</Property>
    </Properties>
    <Appenders>
        <Console name="console" target="SYSTEM_OUT">
            <PatternLayout pattern="%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n" />
        </Console>
        <JTextAreaAppender name="textArea">
            <PatternLayout pattern="[%-5level] %d{yyyy-MM-dd HH:mm:ss} %msg%n">
            </PatternLayout>
        </JTextAreaAppender>
    </Appenders>
    <Loggers>
        <Root level="ERROR">
            <AppenderRef ref="console" level="ERROR"/>
            <AppenderRef ref="textArea" level="ERROR"/>
        </Root>
    </Loggers>
</Configuration>

rgoers is right that it's strange that you have Spring annotations on your Log4j Plugin class. @Configuration and @ComponentScan should not be there. Remove those first. By the way, it's sometimes useful (while debugging log4j2 configs) to set the status to DEBUG like

<Configuration status="ERROR" 

If your plugin is not being recognised, it might be that you don't have annotation processing working. If you are using Gradle, be sure to add log4j-core as an annotationProcessor dependency.

annotationProcessor 'org.apache.logging.log4j:log4j-core'

If you are using IntelliJ, be sure to enable Annotation processing, in Preferences -> Build,Execution, Deployment -> Compiler -> Annotation Processors -> Enable annotation processing.

If that's all okay, Log4J should detect your Appender Plugin, which is the topic of this question.