Java2Script(J2S) provides an Eclipse Java to JavaScript compiler plugin and a JavaScript version of Eclipse SWT besides common utilities like java.lang.* and java.util.*. SWT-based RCP can be converted into RIA by using J2S.
This is a Super Simple Java Editor written entirely in Java. It allows you to compile and run java programs in an mdi interface with syntax highlighting and easy commenting. Currently in suspended development. Available as a jar and an msi.