Unless you put .class in .jar file, you can not execute JAR.
IMHO, the question is valid. What is tested here - I am not the question creator 8-) so doing a guesswork - "java" command can only execute compiled bytecode.
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Joined: Jun 04, 2002
Also, when you run а JAR file, you must anyway spefify Main Class property .class in MANIFEST.MF file.
Joined: Nov 20, 2007
Yeah I agree, but that question could just as easily have been used to trick you in the other direction. "When using the java command, you must specify the .class file." That could have been twisted to be true or false in just the same way. True because you must via the manifest, false because your command only specifies the jar file which in turn specifies the class file.