java runtime environment 32 bit to 64 bit

Due to various additional constraints (such as available swap, kernel address space usage, memory fragmentation, and VM overhead), in practice, the limit is much lower. It means the maximum memory size of your Java process can’t be more than 4GB. In 32-bit JVM maximum, addressable memory space is only 2^32 (i.e.~4gb). On AMD64 and EM64T platforms this difference ranges from 0-15% depending on the amount of pointer accessing your application performs.” If there is a performance hit, why would anyone use 64-bit JVM? The performance difference comparing an application running on a 64-bit platform versus a 32-bit platform on SPARC is on the order of 10-20% degradation when you move to a 64-bit VM.

“Generally, the benefits of being able to address larger amounts of memory come with a small performance loss in 64-bit VMs versus running the same application on a 32-bit VM. Below is the excerpt from Oracle JDK documentation regarding 64-bit JVM performance: 64-bit JVM can have a small performance degradation compared to 32-bit JVM. Most of us think 64-bit is bigger than 32-bit, and that 64-bit JVM performance will be better than 32-bit JVM performance. Does 64-bit JVM perform better than 32-bit JVM?

The subtle difference between 32-bit JVM and 64-bit JVM wouldn’t make much difference to your application. If you aren’t building a performance-critical application, you don’t have to understand the difference. We thought we will try to clarify them through this question-and-answer article Do I need to understand the difference between 32-bit JVM and 64-bit JVM? There are a few distinct differences and subtle nuances between 32-bit JVM and 64-bit JVM.

Java runtime environment 32 bit to 64 bit