keycloak-memoizeit

diff --git a/core/src/main/java/org/keycloak/util/UriUtils.java b/core/src/main/java/org/keycloak/util/UriUtils.java
index 70c6824..f9687a5 100755
--- a/core/src/main/java/org/keycloak/util/UriUtils.java
+++ b/core/src/main/java/org/keycloak/util/UriUtils.java
@@ -63,4 +63,7 @@ public class UriUtils {
         return map;
     }
 
+    public static String stripQueryParam(String url, String name){
+        return url.replaceFirst("[\\?&]"+name+"=[^&]*$|"+name+"=[^&]*&", "");
+    }
 }

diff --git a/core/src/test/java/org/keycloak/util/UriUtilsTest.java b/core/src/test/java/org/keycloak/util/UriUtilsTest.java
index af89777..0740ec2 100644
--- a/core/src/test/java/org/keycloak/util/UriUtilsTest.java
+++ b/core/src/test/java/org/keycloak/util/UriUtilsTest.java
@@ -2,6 +2,7 @@ package org.keycloak.util;
 
 import org.junit.Test;
 
+import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 
@@ -43,4 +44,15 @@ public class UriUtilsTest {
         assertFalse(UriUtils.isOrigin(origin));
     }
 
+    @Test
+    public void testStripQueryParam(){
+        assertEquals("http://localhost",UriUtils.stripQueryParam("http://localhost?login_hint=michael","login_hint"));
+        assertEquals("http://localhost",UriUtils.stripQueryParam("http://localhost?login_hint=michael@me.com","login_hint"));
+        assertEquals("http://localhost?param=test",UriUtils.stripQueryParam("http://localhost?param=test&login_hint=michael","login_hint"));
+        assertEquals("http://localhost?param=test",UriUtils.stripQueryParam("http://localhost?param=test&login_hint=michael@me.com","login_hint"));
+        assertEquals("http://localhost?param=test",UriUtils.stripQueryParam("http://localhost?login_hint=michael&param=test","login_hint"));
+        assertEquals("http://localhost?param=test",UriUtils.stripQueryParam("http://localhost?login_hint=michael@me.com&param=test","login_hint"));
+        assertEquals("http://localhost?pre=test&param=test",UriUtils.stripQueryParam("http://localhost?pre=test&login_hint=michael&param=test","login_hint"));
+        assertEquals("http://localhost?pre=test&param=test",UriUtils.stripQueryParam("http://localhost?pre=test&login_hint=michael@me.com&param=test","login_hint"));
+    }
 }

diff --git a/integration/adapter-core/src/main/java/org/keycloak/adapters/OAuthRequestAuthenticator.java b/integration/adapter-core/src/main/java/org/keycloak/adapters/OAuthRequestAuthenticator.java
index d780f5d..f0f4797 100755
--- a/integration/adapter-core/src/main/java/org/keycloak/adapters/OAuthRequestAuthenticator.java
+++ b/integration/adapter-core/src/main/java/org/keycloak/adapters/OAuthRequestAuthenticator.java
@@ -1,5 +1,6 @@
 package org.keycloak.adapters;
 
+import org.apache.http.client.utils.URIBuilder;
 import org.jboss.logging.Logger;
 import org.keycloak.OAuth2Constants;
 import org.keycloak.RSATokenVerifier;
@@ -10,6 +11,7 @@ import org.keycloak.representations.AccessToken;
 import org.keycloak.representations.AccessTokenResponse;
 import org.keycloak.representations.IDToken;
 import org.keycloak.util.KeycloakUriBuilder;
+import org.keycloak.util.UriUtils;
 
 import java.io.IOException;
 import java.util.UUID;
@@ -125,12 +127,20 @@ public class OAuthRequestAuthenticator {
             if (port != 443) secureUrl.port(port);
             url = secureUrl.build().toString();
         }
-        return deployment.getAuthUrl().clone()
+
+        String loginHint = getQueryParamValue("login_hint");
+        url = UriUtils.stripQueryParam(url,"login_hint");
+
+        KeycloakUriBuilder redirectUriBuilder = deployment.getAuthUrl().clone()
                 .queryParam(OAuth2Constants.CLIENT_ID, deployment.getResourceName())
                 .queryParam(OAuth2Constants.REDIRECT_URI, url)
                 .queryParam(OAuth2Constants.STATE, state)
-                .queryParam("login", "true")
-                .build().toString();
+                .queryParam("login", "true");
+        if(loginHint != null && loginHint.length() > 0){
+            redirectUriBuilder.queryParam("login_hint",loginHint);
+        }
+
+        return redirectUriBuilder.build().toString();
     }
 
     protected int sslRedirectPort() {