This is a mini-tutorial on how to compile and execute a java program.

First read and understand the similar page for the C++ program.

For the graduate class CIS656 I have a set-up similar to that for 
CIS456. I used the java program by one of the students in CIS656. 
He called his program  ReadIpHeader.java , and sent it to me. 
I put it in a directory.
Below you see the full path name of that directory.

The command  ``javac <programname>.java''  causes  the program to be
compiled. The resulting file,  <programname>.class  is not executable.
(no x  among the permission descriptions).  

maan-610 projA>: pwd
/afs/cad.njit.edu/u/o/t/ott/classes/spring06/CIS656/Homework/Tsai/projA
maan-611 projA>: ls -lt
total 26
-rw-r--r--   1 ott      30         13062 Mar 21 15:39 ReadIpHeader.java
maan-612 projA>: javac ReadIpHeader.java
maan-613 projA>: ls -lt
total 40
-rw-r--r--   1 ott      30          6358 Mar 26 13:25 ReadIpHeader.class
-rw-r--r--   1 ott      30         13062 Mar 21 15:39 ReadIpHeader.java
maan-614 projA>: java ReadIpHeader < ../../test_little_in.txt > tsai_out
maan-615 projA>: ls -lt 
total 46
-rw-r--r--   1 ott      30          3046 Mar 26 13:26 tsai_out
-rw-r--r--   1 ott      30          6358 Mar 26 13:25 ReadIpHeader.class
-rw-r--r--   1 ott      30         13062 Mar 21 15:39 ReadIpHeader.java
maan-616 projA>: 

But the file <programname>.class can be run, using the interpreter
``java''. There, input redirection and output redirection is used 
exactly as in C++. That is the line 
``java ReadIpHeader < ../../test_little_in.txt > tsai_out''  .

ls -lt shows that indeed a file tsai_out has been created. I must
check (one way or another: use more, or use cat, or print the file, or
use diff) that that output file has the correct content. I had a very
quick look: It seems that tsai_out is correct.

Do: ``man more'' , ``man cat'' , ``man lpr'' (which in NJIT has a
different name),  ``man lp'' , ``man diff''.