[JAVA-15033] Update article Apache HttpClient 4 Cookbook (#14266)

apache-httpclient4/src/test/java/com/baeldung/httpclient/ClientUtil.java

@@ -0,0 +1,20 @@
+package com.baeldung.httpclient;
+
+import java.io.IOException;
+
+import org.apache.http.HttpEntity;
+import org.apache.http.client.methods.CloseableHttpResponse;
+import org.apache.http.impl.client.CloseableHttpClient;
+
+public final class ClientUtil {
+
+    private ClientUtil(){}
+
+    public static void closeClient(CloseableHttpClient client) throws IOException {
+        if (client == null) {
+            return;
+        }
+
+        client.close();
+    }
+}