ErrorHandler.java

package executor.service.utl;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class ErrorHandler {
    private static final Logger LOGGER = LoggerFactory.getLogger(ErrorHandler.class);
    public static Logger getLogger() {
        return LOGGER;
    }

}

JsonProxySources.java

package executor.service.maintenance.plugin.proxy;

import executor.service.model.ProxyConfigHolderDto;
import executor.service.model.ProxyCredentialsDTO;
import executor.service.model.ProxyNetworkConfigDTO;
import executor.service.utl.ErrorHandler;
import executor.service.utl.Json;

import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;

public class JsonProxySources implements ProxySources {

    private static final String PROXY_LIST_FILENAME = "proxy_list.json";

    private final List<ProxyConfigHolderDto> proxyConfigHolderDtoList = new ArrayList<>();

    public JsonProxySources() {
        parse(PROXY_LIST_FILENAME);
    }

    JsonProxySources(String filename) {
        parse(filename);
    }

    static InputStream getResourceStream(String filename) {
        return JsonProxySources.class.getResourceAsStream("/" + filename);
    }

    @Override
    public List<ProxyConfigHolderDto> getProxyConfigHolders() {
        return proxyConfigHolderDtoList;
    }

    private void parse(String filename) {

        JsonModel[] arr;
        try {
            arr = Json.parseToArrayOrThrow(getResourceStream(filename), JsonModel.class);
        } catch (Exception e) {
            ErrorHandler.getLogger().warn(e.getMessage(), e);
            return;
        }

        for (JsonModel model : arr) {
            for (ProxyCredentialsDTO credentials : model.credential) {
                ProxyConfigHolderDto holder = new ProxyConfigHolderDto(
                        new ProxyNetworkConfigDTO(model.hostname, model.port), credentials
                );
                proxyConfigHolderDtoList.add(holder);
            }
        }

    }

    private static class JsonModel {
        public String hostname;
        public Integer port;

        public List<ProxyCredentialsDTO> credential;
    }
}