troubleshooting suggestions requested

Greetings to all.  I wonder if I might trouble you with a beginner's question.

I have a postgres installation that appears to be working correctly when I used psql to connect to it from the postgres
account. However, when I try to connect as postgres from other accounts, I can't connect.  I think the password has
beenset correctly with ALTER USER from inside psql.  

I get the error:
[rick@localhost javatest]$ e2:Connection refused. Check that the hostname and port are correct and that the postmaster
isaccepting TCP/IP connections. 
Connection refused. Check that the hostname and port are correct and that the postmaster is accepting TCP/IP
connections.
        at org.postgresql.jdbc1.AbstractJdbc1Connection.openConnection(AbstractJdbc1Connection.java:167)
        at org.postgresql.Driver.connect(Driver.java:122)
        at java.sql.DriverManager.getConnection(DriverManager.java:512)
        at java.sql.DriverManager.getConnection(DriverManager.java:171)
        at j5.<init>(j5.java:17)
        at j5.main(j5.java:29)


and the relevant chunk of my code is:
        final static private String _url = "jdbc:postgresql://localhost:5432/wombat1test";
        j5() {
                try {
                Class.forName(_driver);
                c = DriverManager.getConnection(_url, "postgres", "wombatpassport");
                }
                catch (java.sql.SQLException e2) {
                        System.out.println("e2:"+e2.toString());
                        e2.printStackTrace();
                }
====
Clearly, there are quite a few things that could be wrong.  I've been reading the documentation and archive, but my
troubleshootingingenuity is running low.  If  
anyone has any suggestions, I would be very grateful.

Thanks
Rick