I've a problem with Java applets.
I developed two Java applets for my application, the applets are signed with a certificate, include the MANIFEST file with permission and they run correctly.
There is a problem when Oracle releases a new Java update and the applets don't work, it seem that IE look at the latest version of Java and I need to update it every time.
What can cause this problem?
Applets are all but deprecated. Your best bet is to migrate away from them, because more and more browsers are removing support from them.
If you need to enable users to upload files to your server, there are numerous resources and tutorials out there.
Related
We are trying to download something from GE that uses Java to download when logging into the site. This is a windows 7 Professional PC. I have other computers that are able to do this successfully. Here is my order of operations:
Log into the site and select the file I want to download
Click download
It takes me to the page that says it will start in a few seconds but nothing happens. It is supposed to have a box that asks for Java to run.
I have reinstalled Java fresh and still nothing. Tried with multiple user accounts. Added the site to the list of exceptions in the firewalls and Java configuration. I have tried an earlier version of Java. This happens in Mozilla, Chrome and IE. I have made sure that the Java plugin shows up and is enabled. I just cant think of what I am missing. And since we are a contractor GE is not going to help us. Can anyone here think of anything?
Are you sure you have the Java plugin enabled? e.g. in Firefox, go to Settings, Plugins, and change Java Platform SE8 'Next Generation Java Plugin' to 'always activate'?
This sounds similar to the issues I had with Cisco WebVPN, Java-style. Once you have Java installed correctly and set as a plugin for any of the browsers you would like to use, see below.
Before you even start looking at browsers - if you think it is already set up correctly
Look at your Anti-Virus programs or anything else that could prevent it from working. McAfee Host Intrusion Protection is known to cause many Java programs to fail. Kapersky had issues, a while back, with Java on Windows (Java Applets not loading in Windows 8 ).
You must have a 64-bit browser to use 64-bit Java (also mentioned in the Chrome link below).
See below for any specific things that can be modified in the browser.
Chrome 43 is the more complicated browser to set up. They have a dedicated page with instructions.
How do I use Java with the Google Chrome browser?
Firefox 38 will prompt you.
In Internet Explorer 11, it's under Internet Options->Security. I recommend adding the hostname the applet is on as a Trusted Site (Select Trusted Sites and click the Sites button, then add the first part of the url). Click the Custom level button and make sure that Scripting of Java applets is not disabled.
If you still have problems with the applet:
Verify your Java version will work with the applet you are accessing
Verify the plugin is enabled for the browser through the Java Control Panel, which is available in Windows Control Panel, or on Mac/Linux, execute it from the JDK directory ($JAVA_HOME/ControlPanel ).
I ended up fixing the issue. I had to allow their UK site on the list for Java and enable the SSL 2.0 for HTTP in Java config as well
I use Java applets in my application, today I surprisingly saw the redirect from my page and the next message from java
In details I've read about Chrome dropping 'NPAPI' support
Recently, Google has revised their plans and now state that they plan
to completely remove NPAPI by late 2015. As it is unclear if these
dates will be further extended or not, we strongly recommend Java
users consider alternatives to Chrome as soon as possible. Instead, we
recommend Firefox, Internet Explorer and Safari as longer-term
options. As of April 2015, starting with Chrome Version 42, Google has
added an additional step to configuring NPAPI based plugins like Java
to run — see the section Enabling NPAPI in Chrome Version 42 and later
below.
So will it be handled by Java somehow or it is the death of my applet in the next year ?
As of Chrome Version 42, an additional configuration step is required to continue using NPAPI plugins.
In your URL bar, enter:
chrome://flags/#enable-npapi
Click the Enable link for the Enable NPAPI configuration option.
Click the Relaunch button that now appears at the bottom of the configuration page.
So will it be handled by Java somehow ..
If they found a way, that would be a bug in Chrome (that would quickly be fixed).
..or it is the death of my applet in the next year ?
Yep. Not that they were really that 'healthy' for a long time now.
Java applets are not dead. There are a lot of intranet web applications that use them, for instance, for digital signature with applet-javascript-web page interaction. Other option is migration to Firefox.
I saw a demonstration that A Plugin written in Pepper API (PPAPI) can launch an executable and communicate with it. Oracle says at here " This change does not affect Web Start applications, it only impacts applets." But the problem is that browser downloads jnlp file but doesn't launch it. User has to click that jnlp file (of course .jnlp file association should be OK).
I think Oracle write a plugin to launch Web Start application and communicate with it for sending cookie etc. If It is written Applets can convert to Web Start applications with less effort.
I have already asked this and was heavily downvoted. Unfortunately, I still can't solve it. I don't know what I do, but sooner or later I loose an ability to run java applets and java web start applications in all browsers.
Here is an example what is happening.
I am opening page with applets http://csis.pace.edu/~bergin/Java/applets.htm and getting the following picture:
with signs plugins were blocked. I am trying to unblock
which causes another dialog
after OK I have another
next
if clicked
And so on.
Applet doesn't run.
After dancing with PATHes, Java updates and so one, once I can have applet run. But sooner or later I will stuck in this position again.
I would like to know, is it possible to exclude this situation in principle?
I mean I don't want to disable security at all, but I mean that in case my explicit permission everything should run. Is it possible to do that?
UPDATE
First of all, I don't understand, why can't I run applet on outdated java if I want?
I am a human and robots should obey me! :)
Suppose I wish to debug my applet on old version of java, why not?
Second, there is no information about what version it thinks I have and what version it wants?
Without this information it is possible that there is just a bug in version detection mechanism.
I have multiple versions of Java in Program Files since I am a Java developer. Then how can I know which one it uses?
UPDATE 2
I have updated my Java from 1.8.0_20 to 1.8.0_25 and now situation have changed, but applets are sill impossible to run.
The proof I have "latest" java:
The proof I have added the site above to exclusions list:
The effect of applet run:
(applet not runs)
Clicking details result:
(no any details in fact)
So, what to do?
UPDATE 3
This site is not working: http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2012VP113;orb=1;cov=0;log=0;cad=0#orb
(show orbit diagram)
Reloading/restarting browser does not help.
I looked at your html source and realized you're using the .class file directly instead of wrapping it in a jar file. This is what you have:
<applet code="GSort.class" width=700 height=400>
I think applets no longer work when using .class files directly due to new security requirements. They have to be wrapped in jar files because you need to add some security settings to the meta-inf folder of the jar file. Here is how oracle recommends deploying an applet:
https://docs.oracle.com/javase/tutorial/deployment/applet/deployingApplet.html
Edit:
I tried again with adding the site url to the Java security exception list and this time I got it to work! It looks like chrome stays in memory after exiting so changing Java security doesn't affect it unless you shut down chrome completely and restart it. Easiest way is to use Internet Explorer. Try it with Internet Explorer and it should work (assuming that you still have the site added under java security exception list).
Is there a way to point to a specific JRE/JDK location to run a JWS application? I'm looking into specifying the actual location of the JRE, not only it's version via Java SE element of JNLP file. I dont want to access any system JRE, I only want to use whats bundled with my application.
Currently I am trying to bundle 1.6_45 with my app. However I am encountering issues when a user has 1.7_xx JRE installed on their system. It blocks the launch of the webstart application. The jars are self signed and getting them signed by a CA authority is not an option as it is too $$. I changed the j2se version tag in my jnlp to say 1.6* and this allowed it to run with 1.7_xx present. One bug squashed.
Now the issue is that systems are being upgraded to 1.6_71 [private oracle version], that apparently has some 1.7 security fixes backported in it. So now because of the jnlp tag having 1.6*, my app is picking up 1.6_71 and completely hanging. Webstart just opens the java console and hangs. I tried adding -Djnlpx.home to the jnlp java-vm-args, pointing to the bundled jre/bin, but no luck there.
One way I tried [from a post here on SO] is that I created a shortcut to my particular javaws passing the jnlp file location as a parameter. This did not work. It still picked up 1.6_71 and hung.
At this point, if I google anymore, its going to start showing me a captcha...sigh.
Any pointers are greatly appreciated! Thanks!
Is there a way to point to a specific JRE/JDK location to run a JWS application?
Short answer, no. Long answer, nope.
Oracle's latest release of Java 7 Update 51 includes new security changes that will block some applications. This is the new "security baseline" and there is apparently an equivalent code level for 1.6.
One of the configuration options that helps determine what exactly happens is the Security Level, found in the Security tab from (Windows) Control Panel -> Java. If you set the security level at it's lowest (can't remember the name) then you might not get blocked. Security level High will block unsigned and self-signed. Security Level Very High will be even more restrictive, like blocking an expired application - meaning the certificate has expired.
Also, maybe you could try setting the specific level of the JRE you want to run - see the link
http://docs.oracle.com/javase/6/docs/technotes/guides/javaws/developersguide/syntax.html#jnlp
for more info.
Can anyone explain the use of having multiple JRE's in the Control Panel Applet of Java?
Refer to attached snapshot http://ge.tt/5YRkjNm/v/0?c of the location i am referring to.
An applet or desktop app. deployed using Java Web Start can request a specific version of the JRE in the launch file.
Different JREs have different compatibility issues. Code that worked on an earlier version of java may not work on a later version. Also, if there's multiple JREs, it may be hard to decide on one to keep. Thus, it's best to let the user choose.