Error in connecting Oracle database with java Application

try
		{
			Class.forName("oracle.jdbc.driver.OracleDriver");
		}catch(Exception ex)
		{
			System.out.println("Where is your Oracle Driver");
			ex.printStackTrace();
			return;
		}
		
		System.out.println("Oracle JDBC driver registered");
		try
		{
			con = DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:orcl" , "scott" , "ahsan");
		}catch(Exception ex)
		{
			System.out.println("Your connection is faild Plz check database");
			ex.printStackTrace();
			return;
		}

<pre lang="xml">java.sql.SQLException: Io exception: The Network Adapter could not establish the connection
    at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:112)
    at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:146)
    at oracle.jdbc.driver.DatabaseError.throwSqlException(DatabaseError.java:255)
    at oracle.jdbc.driver.T4CConnection.logon(T4CConnection.java:387)
    at oracle.jdbc.driver.PhysicalConnection.&lt;init&gt;(PhysicalConnection.java:414)
    at oracle.jdbc.driver.T4CConnection.&lt;init&gt;(T4CConnection.java:165)
    at oracle.jdbc.driver.T4CDriverExtension.getConnection(T4CDriverExtension.java:35)
    at oracle.jdbc.driver.OracleDriver.connect(OracleDriver.java:801)
    at java.sql.DriverManager.getConnection(Unknown Source)
    at java.sql.DriverManager.getConnection(Unknown Source)
    at database.main(database.java:30)</pre>