Question

Do anyone know when Eclipse plans to move its codebase to > 1.5 (i.e. using generic & annotation)?

Answer 1

Even the latest plan for the upcoming eclipse 3.6 Helios still mentions:

Most of the Eclipse SDK is “pure” Java code and has no direct dependence on the underlying operating system. The chief dependence is therefore on the Java Platform itself.
Portions are targeted to specific classes of operating environments, requiring their source code to only reference facilities available in particular class libraries (e.g. J2ME Foundation 1.1, J2SE 1.4, Java 5, etc).

In general, the 3.6 release of the Eclipse Project is developed on a mix of Java 1.4, Java 5 and Java 6 VMs.
As such, the Eclipse SDK as a whole is targeted at all modern, desktop Java VMs.
Most functionality is available for 1.4 level development everywhere, and extended development capabilities are made available on the VMs that support them.

So as long as they want to support platforms with an old JDK, the incentive to rewrite a large portion of the codebase in recent JDK is low.

Note: e4 (Eclipse 4.0) will be based on Java 5.

In general, the 1.0 release of the e4 Project is developed on Java SE 5.