Fixed - `factory already defined` error during Redisson initialization. #734

redisson/src/main/java/org/redisson/misc/URLBuilder.java

@@ -16,6 +16,7 @@
 package org.redisson.misc;
 
 import java.io.IOException;
+import java.lang.reflect.Field;
 import java.net.InetSocketAddress;
 import java.net.MalformedURLException;
 import java.net.URL;
@@ -41,6 +42,15 @@ public class URLBuilder {
             return;
         }
         init = true;
+        
+        try {
+            Field field = URL.class.getDeclaredField("factory");
+            field.setAccessible(true);
+            final URLStreamHandlerFactory currentFactory = (URLStreamHandlerFactory) field.get(null);
+            if (currentFactory != null) {
+                field.set(null, null);
+            }
+            
             URL.setURLStreamHandlerFactory(new URLStreamHandlerFactory() {
                 @Override
                 public URLStreamHandler createURLStreamHandler(String protocol) {
@@ -60,12 +70,18 @@ public class URLBuilder {
                             protected int hashCode(URL u) {
                                 return u.toString().hashCode();
                             }
-                        
                         };
                     }
+                    
+                    if (currentFactory != null) {
+                        return currentFactory.createURLStreamHandler(protocol);
+                    }
                     return null;
                 }
             });
+        } catch (Exception e) {
+            throw new IllegalStateException(e);
+        }
     }
 
     public static InetSocketAddress toAddress(String url) {