How do I know if Java JDK is installed correctly?

Setting up Java correctly is the most common problem that I have encountered for new COHCAP users.

One common problem associated with an inproperly installed version of Java is that the COHCAP GUI won't open with a background window (see COHCAP screenshots) and/or COHCAP won't output a .log file.

Sometimes the problem can simply be fixed by re-installing Java JDK.

First, make sure that you have Java JDK installed on your computer. There are several versions of Java (Java JRE, etc.), but this is the only one that is guaranteed to work with COHCAP. Also, please make sure you download the right version for your computer:

http://www.oracle.com/technetwork/java/javase/downloads/index.html

If you don't know how to determine if your computer is 32-bit or 64-bit, please check these tutorials.

PC: http://windows.microsoft.com/en-us/windows7/32-bit-and-64-bit-windows-frequently-asked-questions
Mac: http://apple.stackexchange.com/questions/23713/how-do-i-figure-out-if-my-os-is-mac-os-x-32-bit-or-64-bit

If you think Java JDK is properly installed on your computer, confirm please following the following steps:

1) Open a command-line window
-->This is "Terminal" for Mac users and "Command Prompt" for PC users
2) Type "java -h". You should see some text describing the options that you can use to run java via command line (otherwise you will get an error message because "java" is not a recognized command).
3) Type "javac". Again, you should see some text describing the options that you can use to run the java compiler via command line. Strictly speaking, you don't need javac to run the pre-complied version of COHCAP, but this can help check if Java JDK is installed.

If you get an error message at any of these steps, please try again to install Java JDK.

If this doesn't work, please check to make sure that Java is configured correctly. For example, please see if the Windows PATH variable points to the Java directory.

If you still cannot get COHCAP to work properly, try running COHCAP GUI via command line (instead of using the .bat and/or .command files).

Running COHCAP GUI via command line:

1) Open a command-line window
-->This is "Terminal" for Mac users and "Command Prompt" for PC users
2) Move to the "bin" folder within the COHCAP directory
3) Type "java -jar cohcapGUI.jar"

If you cannot even open COHCAP GUI using this command, you may need to recompile the source code for your computer. Please see [Why can't I run COHCAP GUI?] for instructions on how to do this.

If you have tried this troubleshooting and you are still encountering a problem, please copy your error messages from the command-line window and create a new discussion group topic describing your problem.