Blog

We were working on a proof of concept and for that I quickly needed a HashMap with a Time to Live (TTL). Basically, I wanted the keys to expire automatically after a certain time period. Fortunatly, Google Guava provides this out of the box in form of LoadingCache Here is how you would initialize it, private LoadingCache<String, String> cache = CacheBuilder.newBuilder() .maximumSize(Integer.MAX_VALUE) .expireAfterWrite(5, TimeUnit.MINUTES) .build(new CacheLoader<String, String>() { @Override public String load(final String response) throws...

I have been recently focused a lot on Web application security especially web vulnerabilities such as Cross Site Scripting (XSS) and Cross Site Request Forgery (CSRF) One of the interesting protection mechanism around these attacks is Same Origin Policy which I believe every application developer should understand in deep. So what is cross origin policy? Reference: Mozilla docs When a browser loads the web page, the web page elements might refer to other origins (basically...

We all know standard way of traversing trees such as InOrder PostOrder PreOrder However, its good to know some other ways of traversing trees as well. private boolean findNode(TreeNode node, TreeNode n, List<TreeNode> path) { path.add(node); if (node.val == n.val) { return true; } if (node.left != null) { return findNode(node.left, n, path); } if (node.right != null) { return findNode(node.right, n, path); } path.remove(path.size() - 1); return false; } private boolean findNode(TreeNode node, TreeNode...

These days Java developers almost universally prefers Lombok because it cuts down on the boilerplate code you have to write while writing new classes. Specifically, it allows to generate getters, setters, toString, hashCode and constructor function automatically. However, there are some pitfalls which developers must be aware of while using Lombok: For example, when we have boolean fields in our class such as follows: @Getter @Setter public class TestBean { private String str; private boolean...

This extension adds the Format button to the LeetCode code editor. Currently supported programming languages are Java, JavaScript and TypeScript. Available for both Google Chrome and Firefox. Download here for Firefox Download here for Chrome

Quick update that I created a small Firefox extension to view the current online number of visitors from Google Analytics in the browser tab itself. Here its how looks like: The extension can be downloaded from Firefox extensions page

Recently, I read an article on Sockets in your shell and I thought it was amazing find for me. Lot of times especially working with docker, I had to install tools like telnet, nc and curl to check basic connectivity. Little did I realize that this functionality is inbuilt into shell. For ex, let’s say we have a basic http server running in local as follows: const http = require('http'); const requestListener = function (req,...

There was a famous bug which existed in JDK implementation of Binary Search Randomly, I tried to reproduce the issue this weekend. Here is the flawed implementation public int search(int[] arr, int target) { int low = 0; int high = arr.length - 1; while (low <= high) { int mid = (high + low) / 2; if(arr[mid] == target) { return mid; } else if (arr[mid] < target) { low = mid + 1;...

In one our recent requirements, we were required to very accurately split the incoming traffic into multiple distribution patterns. This is a very common algorithm requirement in use cases such as load balancer where you would assign the weight to each resource and load balancer would split the incoming traffic into the resources based on the desired weightages. I had written the article Incrementally routing traffic to newer version of service and an astute follower...

Yesterday, I observed painfully slow debugging in IntelliJ. Every step over or step in took almost 10 seconds to perform. It was a simple Java console application having about some 88k entries in few arrays. I had successfully debugged applications having millions of entries in arrays, lists and maps before without any performance issues. Then I looked at the toString() implementation of the custom object which I was holding in the array public String toString()...