jaxx lets you write Swing user interfaces using XML tags instead of raw java code. I've written a quick jedit mode file for jaxx so that it is a bit nicer to write jaxx code in jedit. Basically, it write paint code inside script tags as java code and code inside style tags as CSS. It would need a bit of work to deal with data binding and the special jaxx css, but it's a start. 
<?xml version="1.0"?>
<!DOCTYPE MODE SYSTEM "xmode.dtd">

<MODE>
  <RULES IGNORE_CASE="FALSE">
        
    <SPAN_REGEXP MATCH_TYPE="MARKUP" 
      DELEGATE="java::MAIN" HASH_CHAR="&lt;">
      <BEGIN>&lt;script&gt;</BEGIN>
      <END>&lt;/script&gt;</END>
    </SPAN_REGEXP>
    
    <SPAN_REGEXP MATCH_TYPE="MARKUP" 
      DELEGATE="css::MAIN" HASH_CHAR="&lt;">
      <BEGIN>&lt;style&gt;</BEGIN>
      <END>&lt;/style&gt;</END>
    </SPAN_REGEXP>
    
    <IMPORT DELEGATE="xml::MAIN" />
  </RULES>

</MODE>
Don't forget to add this line to you catalog file: 
  <MODE NAME="jaxx"   FILE="jaxx.xml" FILE_NAME_GLOB="*.jaxx"  />