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 been set correctly with ALTER USER from inside psql.

I get the error:
[rick(at)localhost javatest]$ e2:Connection refused. Check that the hostname and port are correct and that the postmaster is accepting 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 troubleshooting ingenuity is running low. If
anyone has any suggestions, I would be very grateful.

Thanks
Rick