fix more warnings

Author: Vladimir Kotal

plugins/src/main/java/opengrok/auth/plugin/LdapAttrPlugin.java

@@ -120,10 +120,6 @@ protected boolean sessionExists(HttpServletRequest req) {
                 && req.getSession().getAttribute(sessionAllowed) != null;
     }
 
-    private String getSessionAttrName() {
-        return (LdapUserPlugin.SESSION_ATTR + (ldapUserInstance != null ? ldapUserInstance.toString() : ""));
-    }
-
     String getSessionAllowedAttrName() {
         return sessionAllowed;
     }
@@ -137,7 +133,8 @@ public void fillSession(HttpServletRequest req, User user) {
 
         updateSession(req, false);
 
-        if ((ldapUser = (LdapUser) req.getSession().getAttribute(getSessionAttrName())) == null) {
+        if ((ldapUser = (LdapUser) req.getSession().
+                getAttribute(LdapUserPlugin.getSessionAttrName(ldapUserInstance))) == null) {
             LOGGER.log(Level.WARNING, "cannot get {0} attribute", LdapUserPlugin.SESSION_ATTR);
             return;
         }

plugins/src/main/java/opengrok/auth/plugin/LdapUserPlugin.java

@@ -116,7 +116,7 @@ private void init(Map<String, Object> parameters) {
     @Override
     protected boolean sessionExists(HttpServletRequest req) {
         return super.sessionExists(req)
-                && req.getSession().getAttribute(getSessionAttr()) != null;
+                && req.getSession().getAttribute(getSessionAttrName()) != null;
     }
 
     /**
@@ -204,21 +204,25 @@ public void fillSession(HttpServletRequest req, User user) {
      * @param req the request
      * @param user the new value for user
      */
-    protected void updateSession(HttpServletRequest req, LdapUser user) {
-        req.getSession().setAttribute(getSessionAttr(), user);
+    void updateSession(HttpServletRequest req, LdapUser user) {
+        req.getSession().setAttribute(getSessionAttrName(), user);
     }
 
-    String getSessionAttr() {
+    static String getSessionAttrName(Integer instance) {
         return (SESSION_ATTR + (instance != null ? instance.toString() : ""));
     }
 
+    private String getSessionAttrName() {
+        return getSessionAttrName(instance);
+    }
+
     @Override
     public boolean checkEntity(HttpServletRequest request, Project project) {
-        return request.getSession().getAttribute(getSessionAttr()) != null;
+        return request.getSession().getAttribute(getSessionAttrName()) != null;
     }
 
     @Override
     public boolean checkEntity(HttpServletRequest request, Group group) {
-        return request.getSession().getAttribute(getSessionAttr()) != null;
+        return request.getSession().getAttribute(getSessionAttrName()) != null;
     }
 }

plugins/src/test/java/opengrok/auth/plugin/LdapAttrPluginTest.java

@@ -31,7 +31,6 @@
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashMap;
-import java.util.HashSet;
 import java.util.Map;
 import java.util.Set;
 import java.util.TreeMap;