I home host a Minecraft server and I just updated Java to update 65, the server worked perfectly before updating but now, it says "This Java instance does not support a 64-bit JVM. Please install the desired version." Installing 32-bit Java doesn't help and this also happens when I run my Minecraft client. I have 64-bit Windows 7 running 64-bit Java 7. If anybody can help that would be great.
EDIT: Fixed it, apparently I'm just an idiot and had 32-bit installed when I updated java, and since I thought I had 64-bit installed I never thought to re-install it. Sorry for wasting your time
As the author stated, the solution was pretty simple. Bringing it to an answer to help future users
This java instance does not support a 64-bit JVM
This error is associated with your System looking for a Java 64-bit Virtual Machine and not finding any.
To solve it, you must make sure that the 64-bit Java is installed. The problem the OP had was: He assumed he had the 64-bit installed, but he did not.
To download Java, access Java Website
Because you are using 64 bit minecraft client, you are not able to work even with 32 bit JVM. Kindly install all the things, mincraft server,client, JVM of 32 bit only. You can run it definitely. If still not able to work, let me know with exact error message you are getting.
来源：https://stackoverflow.com/questions/24987440/this-java-instance-does-not-support-a-64-bit-jvm