Installing SSL Certificate on Linux Tomcat Server

SSL (Secure Sockets Layer) is the standard security technology for establishing an encrypted link between a web server and a browser. This link ensures that all data passed between the web server and browsers remain private and integral. With a secure web server, clients can connect to your server secure in the knowledge both that it is who it claims to be and that the transaction is well-encrypted so their data is safe.

• Here are the few steps to install SSL Certificate.

1. First create a keystore file using below command.
keytool -genkey -alias domainname.com -keyalg RSA -keystore keystore.jks -keysize 2048

2.Generate an CSR(Certificate Signing Request).
keytool -certreq -alias domainname.com -keystore keystore.jks -file domainname.csr

3.Import root certificate.
keytool -import -alias root -keystore keystore.jks -trustcacerts -file root.crt

4. Import intermidiate certificate.
keytool -import -alias intermed -keystore keystore.jks -trustcacerts -file intermediate.crt

5. Install your certificate.
keytool -import -alias domainname.com -keystore keystore.jks -trustcacerts -file keystore.crt

• Configuration of connector in Apache - In tomcat server.xml file, you have to add some parameters to the connector tag like SSLEnabled, Address, Keystore file, Password of keystore file etc.

<Connector port="443" protocol="HTTP/1.1" address="192.168.2.111" SSLEnabled="true"
maxThreads="500" scheme="https" secure="true"
clientAuth="false" sslProtocol="TLS"
keystoreFile="/home/user/keystore_yuspeed.jks"
keystorePass="password" />

Direct Memory Access Java

Does Java Allow Direct Memory Access

Well, there is a sun.misc.Unsafe class. It allows direct memory access, so you can implement some magic like reinterpret casts and so on. The thing is you need to use hacky reflection approach to get the instance and this class is not realy well documented. In general you need a very good reason to use this kind of tool in production code.
Here's an example how to get it:

Field f = Unsafe.class.getDeclaredField("theUnsafe");
f.setAccessible(true);
Unsafe unsafe = (Unsafe) f.get(null);

There are 105 methods, allowing different low-level stuff. These methods are devoted to direct memory access:

• allocateMemory
• copyMemory
• freeMemory
• getAddress
• getInt - Gets you a value from the memory whose

 

Method Overidding vs Method Overloading

Difference between overloaded methods and overidden methods in Java

	Overloaded Method	Overridden Method
Arguments	Must change	Must not change
Return type	Can change	Can’t change except for co-variant returns
Exceptions	Can change	Can reduce or eliminate. Must not throw new or broader checked exceptions
Access	Can change	Must not make more restrictive (can be less restrictive)
Invocation	Reference type determines which overloaded version is selected. Happens at compile time.	Object type determines which method is selected. Happens at run-time.