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  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

  Different types of keystore in Java -- Windows-MY

Windows-MY is a type of keystore on Windows which is managed by the Windows operating system. It stores the user keys and certificates which can be used to perform cryptographic operations such as signature verification, data encryption etc. Since it's a kind of native keystore, Java doesn't have a general API to access it. To help Java applications access the keys and certificates stored in Windows-MY keystore, Java provides a separate API -- SunMSCAPI. The SunMSCAPI provider is ...

   JAVA,KEYSTORE,WINDOWS-MY,SUNMSCAPI     2016-01-09 05:45:59

  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

  System programming is still there

System programming is the practice of writing system software. System software lives at a low level, interfacing directly with the kernel and core system libraries. Your shell and your text editor, your compiler and your debugger, your core utilities and system daemons are all system software. But so are the network server, the web server, and the database. These components are entirely system software, primarily if not exclusively interfacing with the kernel and the C library. But nowadays more...

   System programming     2014-02-27 05:46:48

  Android socket programming example

Socket is a kind of interface for different sides t communicate, it usually identified by an IP and a port. There are many server side software on a server and they would provide different service. Each server many create some sockets and bind them to some ports so that clients can listen to. Software on the Internet will exchange data though a bidirectional connection established. Each end of the connection has a socket created. In Java, Socket and ServerSocket are in java.net package, ServerSo...

   Android,Socket,Java     2013-05-11 22:17:16

  Why Use Java?

 Java was developed by Sun Micro-systems back in 1995 to function as high level programming language and serve as a computing platform. This gets regularly updated with new features and better compatibility. The latest version is Java SE 8.0 which released in 2014, March. Java has gained immense popularity while there have been various platforms to match up with the Java configurations like Java SE for Macintosh, Windows and UNIX, Java ME for Mobile Applications and Java EE for Enterpr...

   JAVA APPLICATION DEVELOPMENT,JAVA WEB DEVELOPMENT,JAVA OUTSOURCING COMPANY     2018-07-06 00:05:31

  Why using + to concatenate string in Java loop is not a good option

String concatenation is a common operation in Java programming. It is to concatenate multiple strings into a single string. Java provides a String class which is an immutable class which means the object cannot be mutated once instantiated. Once a String object is instantiated, its properties cannot be changed anymore, so when concatenating strings, it's actually create a new String instance to store the concatenated string values. For example, below is a simple string concatenation example. Str...

   JAVA,STRING,JAVA 8     2019-01-18 22:07:12

  Bing now supports code search

In programmer's daily life, much time is spent on searching Google or StackOverflow for code snippets which can help them understand how the code works. Now there is one more option. Microsoft's Bing now adds a new feature which support code snippet search. With this new feature, you can search code snippet and execute them directly within the search results. For example, if you type "quick sort java", you will see below search result : This feature now supports a few popular programming langua...

   BING,CODE SEARCH,HACKERRANK     2016-04-09 02:49:25

  JShell -- The command line tool to run Java code in Java 9

Java 9 is currently a work-in-progress and is planned to be GAed in March 2017. Quite a few new features will be introduced in the new release. The coolest feature is project Jigsaw which is to modularize the Java packages so that a customized JDK can be built and shipped with only the necessary modules to fulfill their project requirement. Apart from this feature, another big new feature is project Kulla -- JShell. In simple, JShell is a command line tool which can be used to run...

   JAVA 9,JSHELL,KULLA     2016-04-01 21:46:48