Only the six low-order bits of operand2 are used when shifting a 64-bit integer (to prevent shifting more than the number of bits in a 64-bit integer). The shift doesn’t preserve negative values.

For the same reasons any 64-bit application is desirable, to be able to address more than 4G of VM. Although in this case it's not a particular app but the JVM for Java apps so in theory a64-bit ...

IBM plans to make 64-bit Java technology available on its AIX 5L Unix operating system in early July, a move that it claims puts AIX ahead of Sun's Solaris and Hewlett-Packard's HP-UX operating ...

There are no 64-bit versions of the Java Plugin, Java Web Start or Java Control Panel; however the 32-bit versions of the JRE can be installed on 64-bit systems in order to obtain this functionality.