Q:

A file exists but executing it doesn't work

I downloaded a Java tarball, extracted the archive and copied over scp to a remote machine.  Using the ls command, the java executable exists:
ubuntu@Ubuntu:~$ ls -la /home/ubuntu/jre1.7.0_55/bin/
total 420
drwxr-xr-x 2 ubuntu ubuntu   4096 Mar 18 03:54 . 
drwxr-xr-x 6 ubuntu ubuntu   4096 Apr 30 12:55 ..
lrwxrwxrwx 1 ubuntu ubuntu      8 Apr 30 10:58 ControlPanel -> jcontrol
-rwxr-xr-x 1 ubuntu ubuntu   5714 Mar 18 03:53 java
-rwxr-xr-x 1 ubuntu ubuntu  16246 Mar 18 03:54 java_vm
-rwxr-xr-x 1 ubuntu ubuntu 104497 Mar 18 03:54 javaws
-rwxr-xr-x 1 ubuntu ubuntu   6391 Mar 18 03:54 jcontrol
-rwxr-xr-x 1 ubuntu ubuntu   5873 Mar 18 03:53 keytool
-rwxr-xr-x 1 ubuntu ubuntu   6013 Mar 18 03:53 orbd
-rwxr-xr-x 1 ubuntu ubuntu   5893 Mar 18 03:53 pack200
-rwxr-xr-x 1 ubuntu ubuntu   5981 Mar 18 03:53 policytool
-rwxr-xr-x 1 ubuntu ubuntu   5865 Mar 18 03:53 rmid
-rwxr-xr-x 1 ubuntu ubuntu   5877 Mar 18 03:53 rmiregistry
-rwxr-xr-x 1 ubuntu ubuntu   5893 Mar 18 03:53 servertool
-rwxr-xr-x 1 ubuntu ubuntu   6045 Mar 18 03:53 tnameserv
-rwxr-xr-x 1 ubuntu ubuntu 215380 Mar 18 03:53 unpack200

However:
ubuntu@Ubuntu:~$ /home/ubuntu/jre1.7.0_55/bin/java
-bash: /home/ubuntu/jre1.7.0_55/bin/java: No such file or directory

What's the reason? 

A:

Possibly the (Java) binary you are executing ( which is 64 bit binary)  on 32 bit OS

