I tried implementing a singleton class method , which is invoked by a filter class. The filter class and the rest of the classes , are added to WLS as a shared library.
And i have two separate web apps running - servlets with filter - both on the same managed server.
So everything is working fine except , the singleton is getting instantiated twice . plz find below the code snippet.
public class Test
{
private static Test ref ;
private DataSource X;
static int Y;
long Z ;
private Test ()
{
// Singleton
Z= 100 ;
}
public static synchronized Test getinstance() throws NamingException, SQLException
{
if(ref == null)
{
ref = new Test() ;
InitialContext ic = new InitialContext();
ref.X = (DataSource)ic.lookup ("jdbc/Views");
}
return ref ;
}
public Object clone()throws CloneNotSupportedException
{
throw new CloneNotSupportedException();
}
public int sampleMethod (int X) throws SQLException
{
}
}
Filter method:
public final class Filter implements Filter
{
public void doFilter(ServletRequest request, ServletResponse response,FilterChain chain) throws IOException, ServletException
{
try
{
Test ref = Test.getinstance();
log.logNow(ref.toString());
.......
}
}
}
In the log am getting two different references - say
Test@f1a2e06 Test@f180f10
Am i doing something wrong here ? Any help would be great.
A servlet container uses different classloaders for different application. So I don't believe it is possible to share an instance. What you can do is perhaps register the instance via JNDI.
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