Single DB connection

I would like to create a single Database connection point that I can
use for several of my classes in my Java Web Application.

Here is my ConnectionManager Class:

public class ConnectionManager {
private static Connection activeConnection = null;
public static Connection getConnection() {
if (activeConnection = null) {
Class.forName("OracleThinInfoHere...");
activeConnection =
DriverManager.getConnection("jdbc:oracle:thin:@myname:1234:orcl",
"scott", "tiger");
}
return activeConnection;
}
}

Now how would I access the ConnectionManager in each one of my
classes?

For example here is one:

public class MainClass
{

public ConnectionManager.getConnection();
public Connection connection;

//I tried my db connection as this and it didnt return any results
public MainClass(connection)
{
this.connection = ConnectionManager.getConnection();
}

public int matcher(BeanClass abc)
{
try
{
new OtherDbClass(connection).insertDbMethod(abc);
}
catch(Exception e)
{
e.printStackTrace();
}
finally
{
//closing statements here
}

Another Class looks like this:
public class OtherDbClass {
private Connection connection;
public OtherDbClass(Connection connection)
{
this.connection = ConnectionManager.getConnection();
}

public int insertDbMethod(BeanClass abc)
{
....
....
}

Please advise.