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Binary tree post order traverse without recursion in Java

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Post order traversal   In PostOrder traversal, the left node is processed first, the right node (subtree), then the node. Steps for post order are:    1. Process left subtree.    2. Process right subtree.    3. Process the node. I will consider processing the node is just printing out its value on screen. Consider the below binary tree Processing the above tree in post order should result the following:                         1, 4, 6, 2, 12, 45, 40, 10, 75, 60, 50 The recursive solution is very straight forward by following the above steps:     public void postOrderTravesalRecursion(){         postOrderTravesalRecursion(this.root);     }         private void postOrderTravesalRecursion(Node node){                   if(node==null){                return;            }            postOrderTravesalRecursion(node.getLeft());            postOrderTravesalRecursion(node.getRight());            System.out.println(node);     } Doing the same without usi
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Spring 4 Security - Authorization with Roles and Rights

First of all, spring security doesn't support roles/rights security approach. It has two basic security approaches: Simple, role-based security without rights. Complex ACL based security that defines permissions at the domain object level.  I will not go through ACL based security because most applications need a way less than the complex approach. I will show you how to tweak the simple approach to implement roles/rights security. 1. Configuring spring security filter in web.xml <filter> <filter-name>springSecurityFilterChain</filter-name> <filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class> </filter> <filter-mapping> <filter-name>springSecurityFilterChain</filter-name> <url-pattern>/*</url-pattern> </filter-mapping> We must configure spring to load spring-secuirty.xml for security configurations <context-pa
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