learn-java

Here we will learn some of the concepts about Java.

Serialization and Deserialization of object:

Serialization and deserialization of object is one of the important task which is generally being used inside the application. Here we will demonstrated diffrent types of serialization and deserialization technique.

• Firsly, we will show using (ObjectOutputStream/ObjectInputStream and FileOutputStream/FileInputStream).

• Concept of serialVersionUID

    Each class has its own serialVersionUID, which depends on the structure of the class.
  

  It is used at the time serialization and deserialization. For the compatibility serialVersionUID should be same at both of the time. Since some of the changes in class may not hurt deserialization like add a new instance variables. But due to change in class serialVersionUID will be change which may result problem at the time of deserialization. Hence we give a final serialVersionUID for a class which remains constant for the class.

Message Passing using Socket Networking:

• A Socket connection means the two machines have information about each other, including network location (IP address) and TCP port.

• Socket provides InputStream for reading a message and OutputStream for writing something.

• Here, we only illustrated a simple demo of message passing b/w two devices using socket.

Multi-Threading

• A thread is a separate 'thread of execution'. In other words a separate call stack.

• main() method is also a thread called by JVM.

• Just pass a runnable instance to Thread constructor to create a thread. Call start() method of thread to get in Runnable state of a thread. Execution of the thread is controlled by Thread schedular.

• 'synchronized' keyword is used to make a method atomic.

• Need to handle deadlock when you are working on multi-threaded application.