Most binaries were still 32-bit for performance reason, and I don't think that Java 1.2 had a 64-bit port yet, not even on Solaris/SPARC.
The situation that an x86-64 build is faster than an i386 build of most applications (exception extremely pointer-heavy ones) is a bit of an exception because x86-64 added additional registers and uses a register-based calling convention everywhere. That happens to counteract the overhead of 64-bit pointers in most cases. Other 64-bit architectures with 32-bit userspace compatibility kept using 32-bit userspace for quite some time.
The situation that an x86-64 build is faster than an i386 build of most applications (exception extremely pointer-heavy ones) is a bit of an exception because x86-64 added additional registers and uses a register-based calling convention everywhere. That happens to counteract the overhead of 64-bit pointers in most cases. Other 64-bit architectures with 32-bit userspace compatibility kept using 32-bit userspace for quite some time.