Tasklist will show you the details.
@ECHO OFF
SETLOCAL
SET "underline="
SET "mypid="
FOR /f "skip=2delims=" %%u IN ('tasklist/v') DO IF NOT DEFINED underline SET underline=%%u
FOR /f "delims=" %%u IN ('tasklist/v^|find /i "GPU Client"') DO IF NOT DEFINED mypid SET mypid=%%u
:loop
IF "%underline:~0,1%"=="=" SET underline=%underline:~1%&SET mypid=%mypid:~1%&GOTO loop
FOR %%u IN (%mypid%) DO IF DEFINED underline SET mypid=%%u&SET "underline="
echo Target process ID=%mypid%
GOTO :EOF
This should get the process ID ready for TASKKILL. The string GPU Client should be replaced by a uniwue string identifying the java process that you wish to terminate, which you should be able to derive from a tasklist listing from the prompt.
tasklist /v
The length of the underline appearing under the tasklist /v report heading varies depending on the length of the longest name of tasks currently running, so the underline line is applied to underline, the selected detail line to mypid and then the first character of each string is trimmed off until the space in the line-of-= is found.
At this time, mypid will have the taskname trimmed off, so its first token is the PID.