Sun has posted the second beta of Java 1.5 (excuse me, Java™ 2 Standard Edition Software Development Kit 1.5) for Windows, Linux, and Solaris. Itanium chips are not yet supported.
Etienne Gagnon has released version 1.1.5 of SableVM, a Java bytecode interpreter (that is, a virtual machine) written in portable C. "SableVM requires an ANSI/ISO C compiler (but preferably GCC) and a POSIX platform. It requires a strong memory model (sequential consistency) on multiprocessor systems." SableVM is available for GNU/Linux. Solaris, Mac OS X, and FreeBSD. Version 1.1.5 improves support for Ant 1.6 and fixes a number of bugs. SableVM is published under the GNU Lesser General Public License (LGPL).