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  Generate certificate in Java -- Certificate chain

In previous post, we have introduced the use of Certificate and how to generate self signed certificate using Java. In this post, we will show you how to generate a certificate chain. Sometimes we may only have a certificate request or we don't have a trusted certificate which can be used for business. Now we need to have a trusted CA to sign our certificate so that it can be used on SSL communications. To generate a certificate chain, we may first have our own certificate(A), then we may use ot...

   Java,Certificate chain,Creation, Pure Java     2014-07-30 08:24:52

  Error handling in GoLang

Error handling is one of the must talked topics for any programming language. The program would be more reliable and stable if errors are handled properly and timely. Each programming language has its own way to handle error, this applies to GoLang as well. This post will discuss more about GoLang's error handling mechanism. Error handling Before talking more about GoLang's error handling, we can see how different programming languages are handling errors. C's error check The most direct way of ...

   GOLANG,ERROR HANDLING,FLUENT INTERFACE     2021-03-06 21:36:08

  Singleton Design Pattern in Java

Singleton is frequently used in applications where resource may be expensive to create and no instance specific state needs to be maintained. For example, when creating database connection, a singleton may be needed. Today we will share the famous Singleton design pattern in Java. 1. Definition Singleton design pattern is a design pattern that restricts the instantiation of a class to one object. It is one of the most well-known design patterns. 2. Application Singleton ...

   DESIGN PATTERN,SINGLETON,MULTITHREAD,JAVA     2020-04-11 02:16:28

  Generating CSR using Java

A CSR(Certificate Signing Request) is a kind of request generated by an application and is to be sent to a Certificate Authority to create a signed certificate which can be distributed. It usually contains certificate information such as subject name, public key info and signature info. In Java, keytool can be used to generate a certificate request with option -certreq.  But sometimes if an application wants to create a CSR programmatically, keytool will not do a favor, instead you should u...

   JAVA,SECURITY,CSR,CERTIFICATE REQUEST     2016-05-25 04:49:17

  Tomcat vs. Apache: Why One Over the Other?

When determining which type of web server to use, the differences and technical details can be daunting. It can be a difficult task to compare web servers and make the decision on which is best for you and your project. Since Apache is currently the most popular web server, this article will discuss the differences between the Apache Web Server and Apache Tomcat, which are very different and fulfill different needs.The Apache Web Server, often just called “Apache” or â€...

   Apache,Tomcat,Choice,Web server     2012-03-23 12:01:25

  6 Great Ways to Design Amazing PWA’s

Why PWA v/s Native Mobile apps a wrong question to ask. PWA has already gathered a lot of momentum recently and is structured to give “App like” experience to its user base. Reveal all the extra layers underneath and create magic with brand new ideas to design progressive web apps. What comes to your mind when you imagine leading a progressive life? Definitely, it is going to be far better than  the previous one. Progressive Web Apps (PWA’s) are going to work to outweigh ...

   WEB DESIGN,PROGRESSIVE WEB APPS,PROGRESSIVE WEB APP TECHNOLOGY,COMMON UI/UX MISTAKES     2018-02-28 03:30:46

  Convert JKS to BKS using keytool

There are lots of questions(question 1, question 2) on Stackoverflow about how to convert JKS keystore to BKS keystore(a keystore format provided by BouncyCastle) using Java keytool.  The reason why this conversion gets lots of questions is that BKS is not a keystore format supported by Java SE, it's a third party keystore format. To convert JSK to BKS, the BKS provider has to be downloaded first. And a few more options needs to be added when running the keytool command. The typical co...

   JKS,BKS,KEYTOOL,JAVA,SECURITY     2016-07-14 03:49:52

  Java Cipher encryption/decryption example

In Java, Cipher is the API for doing data encryption/decryption. Many cryptographic algorithms such as AES, DES, RC4 etc can be specified when creating Cipher instance. The Cipher instance calls the underlying algorithm specific implementation to do the actual encryption/decryption.  Before doing the encryption/decryption, a key needs to be created and it will be used to do the encryption/decryption. A sample program for performing all these is : import java.security.Key; import javax.cryp...

   Java, Java Security, Cipher, Example, Sample     2015-08-14 07:07:10

  Why exception would be thrown when deleting element while looping through HashMap in Java

HashMap and other Collection types are frequently used in Java application programming. This post will explain why exception would be thrown when deleting element with Map.remove() while looping through a Map using Iterator. This issue would also occur to other Collection types such as Set, List. Below is a sample code snippet demonstrating the exception thrown. Map<String,String> map = Collections.synchronizedMap(new TreeMap<String,String>()); map.put("key1","value1"); map.put("ke...

   JAVA,HASHMAP,CONCURRENTMODIFICATIONEXCEPTION     2018-06-30 12:49:09

  10 Points about Java heap memory

When I started java programming I didn't know what is java heap or what is heap space in Java, I was even not aware of where does object in Java gets created, it’s when I started doing professional programming I came across error java.lang.outofmemoryerror then I realized What is Heap in Java or Java Heap Space. Its happens with most of programmer because learning language is easy but learning basics is difficult since there is no formal process which can teach you every basics of pro...

   Java,Heap memory,Tips     2012-02-20 05:38:06