It seems that the shell executing the command is not same as that you are using to run the script on command line. Specify the shell as bash.
Add shebang in the script (as first line). It is always a good practice to be specific about the shell in the script
#!/bin/bash
You could also specify the shell you want to use for the shell script
String[] command = {"/bin/bash", "/home/pi/tbe/testSleep.sh"};