java.lang.ClassNotFoundException: javax.servlet.AsyncContext

I updated my project to Spring 4 and got error:

java.lang.ClassNotFoundException: javax.servlet.AsyncContext

After some googling I found the problem: AsyncContext was introduced into Servlet API 3.0, but I was using Servlet API 2.5. So, the solution is simple - add the following Maven dependency:

Could not find the required version of the Java(TM) 2 Runtime Environment

Today I wanted to install Java EE 7 SDK. I downloaded installer from Oracle's website and when I wanted to run it - I got an error, saying "Could not find the required version of the Java(TM) 2 Runtime Environment".
Ok, I know that I must have Java JRE to run installer of Java EE. But I have Java JRE... So... After some googling I found a solution - to run installation with option -j :


> java_ee_sdk-7-jdk7-windows-x64.exe -j "C:\Program Files\Java\jdk1.7

How to generate public/private keypair with RSA?

I'm developing several projects which use public/private key cryptography. So, the question is simple: how to generate public/private key pair?

As for me, I use OPENSSL to generate RSA key pair. It's simple:

openssl genrsa -out mykey.pem 2048

And public key can be generated like this:


openssl rsa -in mykey.pem -pubout > mykey.pub