You don't need to remove older vesrion of java.
You can proceed with installation of newer java version on non-global zone, no need to install on global zone.
If you have whole root zone,
- Just download jdk tar/sh file, copy it and extract.
- Run "which java" and find out current java path.
- Change symbolic link "/usr/bin/java" to point to new java version.
If you have sparse root, don't change symbolic link "/usr/bin/java", instead change your PATH variable in /etc/profile file. Bcz changing symbolic link may affect functionality of other non-global and global zone.
Please reply back in case of further queries.