Eclipse Help Will Not Display Under Ubuntu

Question

When I open any help in eclipse, I get a page with the message:

Server error. The following error occurred: [code = CANT_CONNECT_LOOPBACK] Unable to connect due to possible loop problems.

I am running Ubuntu 10.04.

Any ideas what this could be?

UPDATE Some commands come out (some personal data is replaced):

$ ifconfig -a eth0 Link encap:Ethernet HWaddr 00:xx:xx:xx:xx:xx inet addr:123.12.123.235 Bcast:123.12.456.255 Mask:255.255.254.0 inet6 addr: fe80::xxx:eff:xxxx:xxxx/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:1343040 errors:0 dropped:0 overruns:0 frame:0 TX packets:1133672 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:829265876 (829.2 MB) TX bytes:242912202 (242.9 MB) Memory:f3200000-f3220000 lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:16436 Metric:1 RX packets:125 errors:0 dropped:0 overruns:0 frame:0 TX packets:125 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:15910 (15.9 KB) TX bytes:15910 (15.9 KB) $ route -n Kernel IP routing table Destination Gateway Genmask Flags Metric Ref Use Iface 123.12.123.0 0.0.0.0 255.255.254.0 U 1 0 0 eth0 169.254.0.0 0.0.0.0 255.255.0.0 U 1000 0 0 eth0 0.0.0.0 123.12.456.254 0.0.0.0 UG 0 0 0 eth0 $ sudo netstat -anp Active Internet connections (servers and established) Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name tcp 0 0 0.0.0.0:111 0.0.0.0:* LISTEN 765/portmap tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN 871/sshd tcp 0 0 127.0.0.1:631 0.0.0.0:* LISTEN 1181/cupsd tcp 0 0 0.0.0.0:52068 0.0.0.0:* LISTEN 786/rpc.statd tcp 0 0 127.0.0.1:3306 0.0.0.0:* LISTEN 1186/mysqld tcp 0 0 0.0.0.0:53709 0.0.0.0:* LISTEN - tcp 0 0 123.12.123.235:755 123.12.5.48:2049 ESTABLISHED - tcp 0 0 123.12.123.235:60793 123.12.5.129:8080 ESTABLISHED 2264/firefox-bin tcp 0 0 123.12.123.235:57940 123.12.5.43:8080 ESTABLISHED 2264/firefox-bin tcp 0 0 123.12.123.235:57928 123.12.5.43:8080 CLOSE_WAIT 2247/google-chrome tcp 0 0 123.12.123.235:35767 123.12.5.129:8080 ESTABLISHED 2247/google-chrome tcp 0 0 123.12.123.235:57930 123.12.5.43:8080 ESTABLISHED 2247/google-chrome tcp 0 0 123.12.123.235:57931 123.12.5.43:8080 CLOSE_WAIT 2247/google-chrome tcp6 0 0 :::80 :::* LISTEN 1278/apache2 tcp6 0 0 :::22 :::* LISTEN 871/sshd tcp6 0 0 ::1:631 :::* LISTEN 1181/cupsd tcp6 0 0 :::55934 :::* LISTEN 1956/eclipse tcp6 0 0 :::5900 :::* LISTEN 1792/vino-server udp 0 0 0.0.0.0:35631 0.0.0.0:* 912/avahi-daemon: r udp 0 0 0.0.0.0:962 0.0.0.0:* 786/rpc.statd udp 0 0 0.0.0.0:68 0.0.0.0:* 1575/dhclient udp 0 0 0.0.0.0:46149 0.0.0.0:* - udp 0 0 0.0.0.0:5353 0.0.0.0:* 912/avahi-daemon: r udp 0 0 0.0.0.0:111 0.0.0.0:* 765/portmap udp 0 0 0.0.0.0:36211 0.0.0.0:* 786/rpc.statd udp 0 0 123.12.123.235:123 0.0.0.0:* 1689/ntpd udp 0 0 127.0.0.1:123 0.0.0.0:* 1689/ntpd udp 0 0 0.0.0.0:123 0.0.0.0:* 1689/ntpd udp6 0 0 fe80::227:eff:fe07::123 :::* 1689/ntpd udp6 0 0 ::1:123 :::* 1689/ntpd udp6 0 0 :::123 :::* 1689/ntpd 

Active UNIX domain sockets (servers and established) due to message size limitations.

UPDATE 2 My proxy settings:

Answer 1

I know this is a late answer, but I had the same problem and resolved it to tie this ...

This is a combination of two errors:

(i) The Eclipse internal help browser does not use the Eclipse proxy settings! See: https://bugs.eclipse.org/bugs/show_bug.cgi?id=318969

(and the errors mentioned in comment # 7 in it)

(ii) Ubuntu proxy support is badly broken in certain subtle ways. See: https://bugs.launchpad.net/ubuntu/+bug/300271

The fix / workaround is to manually set the no_proxy environment variable before running eclipse (as indicated by Eclipse # 308035, referencing 318969), for example.

 export no_proxy=127.0.0.1,localhost eclipse & 

Then Help runs correctly in Eclipse. Of course, as soon as Eclipse starts up (thus launching its own internal HTTP server), you can also access local help information manually from another browser (or, if the “do not access 127.0.0.1” screen is on, there is an icon on top to launch in an external window → system default browser).

This may be applicable to other Linux distributions using Gnome.

[Failed to publish the link with error 308035, because my low reputation means that I can publish only 2 hyperlinks :-( When this privilege is raised, 10 reputation points come: -)]

Answer 2

Basically, this error means that Eclipse cannot establish a TCP / IP connection with your local host using 127.0.0.1 (Eclipse starts the server for reference).

If you use some proxy settings (global at the OS level or local at the Eclipse level), double check that you bypass the proxy server for localhost and 127.0.0.1 .

If this does not help, try setting the host name that help uses for localhost when starting eclipse (either on the command line or in eclipse.ini):

 eclipse -vmargs -Dserver_host=localhost 

Answer 3

Eclipse Help is actually an HTTP server.

This is probably a permissions issue when installing Eclipse.

I have no suggestions other than checking permissions on the Eclipse folder or uninstalling and reinstalling Eclipse.

Answer 4

had the same problem as installing and starting Eclipse in 9.10. It was found that the default settings for Eclipse are fine, but 9.10 did not have a proxy proxy set for 127.0.0.1 in its system settings. I also had to install Apache2 via Synaptic. I installed Apache2, did not change any settings for Apache2, and then sent System> Preferences> Network Proxy Preferences by clicking on Ignored Hosts and adding "127.0.0.1". Reset Eclipse network settings will revert to default, restart Eclipse, and help to work perfectly. Hope this works for others.

Answer 5

David, thanks for the output of netstat ; You will notice that Eclipse is listening on the IPv6 port:

Prototype Recv-Q Send-local address of local address State of external address PID / Program name

tcp6 0 0: 55934: * LISTEN 1956 / eclipse

Is your proxy configuration set to bypass both 127.0.0.1 and :: 1?

Answer 6

Make sure your /etc/hosts executed correctly. Usually

• If the line containing 127.0.0.1 has your host name, delete it and just leave "localhost"
• If the opposite was true, try adding your name to it :)

such things happen because gnome tries to match the hostname and sockets to handle the user interface. Perhaps you should ask the superuser.