import org.apache.http.Header;

import org.apache.http.HttpResponse;

import org.apache.http.client.HttpClient;

import org.apache.http.client.methods.HttpGet;

import org.apache.http.impl.client.HttpClientBuilder;

import org.apache.http.util.EntityUtils;

String address = "http://localhost:8081/admin";

String authorization = "Authorization";

String baseCode = "Basic dGVzdDp0ZXN0";

HttpClient client = HttpClientBuilder.create().build();

HttpGet request = new HttpGet(address);

request.addHeader(authorization, baseCode);

HttpResponse response = client.execute(request);

return EntityUtils.toString(response.getEntity());    

import org.apache.commons.httpclient.HttpClient;

import org.apache.commons.httpclient.HttpException;

import org.apache.commons.httpclient.HttpStatus;

import org.apache.commons.httpclient.methods.GetMethod;

HttpClient client = new HttpClient();

GetMethod method = new GetMethod(url);

int statusCode = client.executeMethod(method);

return method.getResponseBodyAsString();