Java copy/paste problems:

After Java 1.6.23, Java by default eliminated the clipboard copy/paste feature from the JRE to limit security problems in the browser. There are a number of solutions, but the simplest is to just return to the status quo ante - ie, ignore the security risks and just allow copy/paste.
Here's how to do that by changing the setting the java.policy file.

See notes from:

http://www.sqlinform.com/forum4/read.php?3,467
https://bugzilla.redhat.com/show_bug.cgi?id=689157
http://docs.oracle.com/javase/tutorial/deployment/webstart/ - a more secure version which asks the user for clipboard access permission first, but still seems to have essentially the same problems

Find a current version of the java.policy file. Typically find it in:

C:\Program Files\Java\jdk1.7.0_02\jre\lib\security
C:\Program Files\Java\jre7\lib\security

Find the right place to put a copy of it - the place your browsers look for various (lots of) configuration files. Most reliable seems to be to open the Java Console associated with running Java applets.

Start a Java applet in any browser of your choice. The following is a simple choice:
http://java.sun.com/applets/jdk/1.4/demo/applets/SortDemo/example1.html
Open the Java Console window - it should appear on your Task Bar, where you see the Start icon, among other things.
Press "s" to show "dump system and deployment properties"
Look for the line starting with: "deployment.user.security.policy = ", which should be followed by some path similar to:
file:/C:/Documents%20and%20Settings/HP_Administrator/Application%20Data/Sun/Java/Deployment/security/java.policy
This is the place to paste the copy of the java.policy file you made in the previous step.

Edit this file. I suggest using Wordpad. Add the following line:
Restart your browser(s).
Copy/paste should now work!