64-bit pointers isn't really an optimistic assumption, it's just the normal pointer size on 64-bit systems.
The weird inconsistency is apparent as you fairly frequently stub your toe on the 2 billion size limits of Java arrays, which is an area where 64 bit pointers would have made much more size than in object references.
No they weren't, not in the enterprise market. At home? sure.
SUN Microsystems released the Sparc v9 architecture in 1993. SUN also made the Java language and JVM.
There a was HotJava browser, weren't servers just a small part of its target?
There's Java Card for smartcards yes. There was also Java Micro Edition (j2me) for phones.
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.
C and C++ usually do that too.
Interestingly, I can't find any information on Google about this, but ChatGPT does support this. Unfortunately all the primary sources it gave me are for docs that no longer exist on the web. The Wayback machine was no help. The old web is dead :(
Or perhaps that never existed. It's well known that ChatGPT often hallucinates non-existing references (see for instance the discussion at https://news.ycombinator.com/item?id=33841672).
It's unclear whether it's actually a 64-bit build. Did Windows even have a 64-bit userspace on Alpha, or was it all ILP32?
Anyway, it's not really possible to implement the Java memory model on Alpha: https://www.cs.umd.edu/~pugh/java/memoryModel/AlphaReorderin... So it's not really a natural target for Java code.
Ouch!