Can Veryant recommend a good Web site to find 3rd party JavaBeans?

There are many JavaBean graphical controls available that you can include in a COBOL screen section.
For example, ComponentSource has a section devoted to Java components, at http://www.componentsource.com/features/java-components/index.html.

There are also free JavaBean controls available. One of the easiest ways to find these is to use Google and search for the capability you require.
For example, if you need a data grid control then search for "javabean data grid control".
Note that on the web JavaBean is usually one word, though some people add a space: "Java Bean". So if you don't find it with "javabean" you might try "java bean".
If you have a specific control in mind, let us know and we can make a recommendation.

You can also integrate with 3rd party Java technologies that are not JavaBeans.
Veryant Support can assist you with that if you tell us more about the specific function or feature you want.

Note that isCOBOL Evolve includes samples for the various ways COBOL can integrate with other Java technologies (including ISCONTROLSET and programs in the is-java/javabeans folder).
There is also a chapter in the isCOBOL Evolve documentation, under User Interface/Controls Reference/Java-Bean that will give you more information on this subject.