Hi, I tried to set up a modded minecraft server so me and some friends could play, i put all the mods in the server, and i have the same mods in my client, but whenever i try to run it i get this error. It is in minecraft 1.7.10, all the mods and forge are 1.7.10, and i have the same forge version in the client and server. I ran a server the same day not modded and it worked perfectly fine.
Try updating forge to the recommended build 1291 i believe.
There have been reports of issues with java 8 builds and minecraft, if all else fails you could try downgrading to a Java 7 build. However I would not recommend doing this as older Java versions tend to have security/performance issues.
Windows 8.1 64-bit
Java 8u11
forge version 1.7.10-10.13.2.1230.
minecraft 1.7.10
There have been reports of issues with java 8 builds and minecraft, if all else fails you could try downgrading to a Java 7 build. However I would not recommend doing this as older Java versions tend to have security/performance issues.