Skip to main content

Basic Thread’s States

Life cycle of the thread is valuable in the large multithreading application. State of a thread specifies the current activities of the thread at any movement. There are four basic state of the thread.
1.     New – when the object of the class that representing a thread after creating the object, is created then before call the start method the thread can’t run. So it is called new state of the thread or in other words we can say that the thread is said to be in new state. It means the thread has been created and it is ready to run.

2.     Runnable --Thread exists in several states. A thread that has been just created is in the new state. The thread remains in this state until the thread’s start method is called. This causes the thread to enter the runnable (ready) state when the system assigns a processor to the thread

  1. Running – A thread is said to be in the running state if it is executing instructions. The instructions are placed in the run method and when the run method is executing, and then the thread is in the running state. The run method is called by the start() method automatically.

  1. Dead- when the thread returns from run method, it is said to be in the dead state. After the return from the run() the thread instance will available for latter use .

  1. Blocked the thread could be run but there is something that prevents it. While in the blocked state the scheduler will simply skip over it and not give it any CPU time. Until a thread re-entered the running state it will not perform any operations.

Checking the thread state

New release 5.0 of java provides the facility to check the state of the thread at any instance. When the method getState() is called on a thread, one of the following Thread.State values is returned:
·         NEW
·         RUNNABLE
·         BLOCKED
·         WAITING
·         TERMINATED


Popular posts from this blog

Using HyperSQL (HSQLDB)

HSQLDB is a portable RDBMS implemented in pure java. It can be embedded with your application as well as can be used separately. It is very a small database that supports almost all features of the standard database system. It comes with small jar file that can be found in lib folder. The HSQLDB jar package is located in the /lib directory of the ZIP package and contains several components and programs. Core components of jar file are : HyperSQL RDBMS Engine (HSQLDB), HyperSQL JDBC Driver, Database Manager, and Sql Tool. Installing and Using Download: download latest release of HyperSQL database from website and extract it. You will see following contents. Here "bin" directory contains some batch files those can be used to run a swing based GUI tool. You can use runManagerSwing.bat to connect to database, but database must be on before running it. Directory lib contains File hsqldb.jar . It is the database to be used by you. Running database First

In Process Mode of HSQLDB in web application.

If you want to use the database into your web application, you can use the HSQLDB in In_Process mode. In this mode, you can embed the HSQLDB into your web application and it runs as a part of your web application programm in the same JVM. In this mode, the database does not open any port to connect to the application on the hosing machine and you don't need to configure anything to access it. Database is not expposed to other application and can not be accessed from any dabase tools like dbVisualizer etc. In this mode ,database will be unknown from any other person except you. But in the 1.8.0 version, you can use Server intance for external as well as in process access.  To close the databse, you can issue SHUTDOWN command as an SQL query.   In the in-process mode, database starts from JDBC with the associated databse file provided through  connection URL. for example   DriverManager.getConnection("jdbc:hsqldb:mydatabase","SA","");   Here myd

Write a code for servlet which will display all the fields of Employee table in tabular form.MCS-051,Dec09-3a

import javax.servlet.*; import*; import java.sql.*;   import javax.servlet.http.*;   public class Employee extends HttpServlet   {   public void doGet(HttpServletRequest req, HttpServletResponse res) throws IOException,      ServletException   {   res.setContentType("text/Html");   PrintWriter pw = res.getWriter();   try   {   Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");   Connection con=DriverManager.getConnection("jdbc:odbc:dsn");   Statement st=con.createStatement();   ResultSet rs=st.executeQuery("select emp_id,emp_name,emp_dob,mob_no,email from employee");   String tr="";   while({   tr=tr+"<tr>";   tr=tr+"<td>"+rs.getString(1)+"</td>";   tr=tr+"<td>"+rs.getString(2)+"</td>";   tr=tr+"<td>"+rs.getString(3)+"</td>";   tr=tr+"<td>"+rs.getString(4)+"</td>&