I am not able launch JNLP applications using "Java Web Start"? [closed]

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Up until recently, I was able to launch/open JNLP files in Firefox using Java web start. Don't know what happened all of a sudden JNLP files stopped launching, a splash screen appears saying Java Starting. and then nothing happens. Even the Java Console in the browser and javacpl.cpl applet doesn't open. Tried all possibilities: removed all older version and installed the latest JRE (java version "1.6.0_17"), still it doesn't work. Done some googling for this problem, people suggested to start javaws.exe with -viewer option but same behavior (a splash screen appears saying "Java Starting. " and then disappears) The problem is that I don't know any place (logs etc.) to look for to see what is causing the problem. I am using WinXP SP3, and some of the screenshots below shows further info about my system. I can provide any other detail if required but please help me solve this problem.

17 Answers 17

i had the same problem here. go to your Java Control Panel and Settings. Uncheck 'Keep temporary files on my computer'. Apply changes and try again your .jnlp

Note: Tested on different machines; Windows Server 2012, Windows Server 2008 and Windows 7 64bit. Java Version: 1.7++ since my jnlp app is built on 1.7

Please let me know your feedback too. :D

Magically working also under Sonoma 14.6.1, Java(TM) SE Runtime Environment (build 18.0.2.1+1-1), Java HotSpot(TM) 64-Bit Server VM (build 18.0.2.1+1-1, mixed mode, sharing)

Java web start should be enabled.
Check if javaws (Java web start is enabled for your system), Use below command in console to open java control panel.

javaws -viewer 

This helped me, as all other options like associate file system modification in control panel, java security enable site lists are added etc, one thing pending for me was this!

I know this is an older question but this past week I started to get a similar problem, so I leave here some notes regarding the solution that fits me.

This happened only in some Windows machines using even the last JRE to date (1.8.0_45).

The Java Web Start started to load but nothing happened and none of the previous solution attempts worked.

After some digging i've found this thread, which gives the same setup and a great explanation.

So, in conclusion, it was a memory problem in x86 JRE and since our JNLP's max heap was defined as 1024MB, we changed to 780MB as suggested and it was fixed.

However, if you need more than 780MB, can always try launching in a x64 JRE version.

Great, that works. In our case, -Xms in the JNPL file must be equal to the -Xmx set in _JAVA_OPTIONS.

If javacpl does not open and gives you Could not find the main class:, it could be that Java is confused because of changes in deployment.properties (can be found in C:\Users\\AppData\LocalLow\Sun\Java\Deployment on Win7 ). Delete that file and everything's fine.

This bug seems to be 6 years old, cf. An app should be able to ignore properties that have become obsolete over time, shouldn't it?

Although this question is bit old, the issue was caused by corrupted ClearType registry setting and resolved by fixing it, as described in this ClearType, install4j and case of Java bug post.