330 Java Tips.pdf - FTP Server

Operational Systems & Java
}
}
if (line == null)
break;
nLines++;
System.out.println(nLines + ":" + line);
If there is a way to run a java program by just typing the name in UNIX. I mean
instead of typing for example "java Main" just type "Main" and run the program. And
how to implement that in a makefile?
Answer: Write a script that runs the program and put it in your path. For
instance:
#!/bin/sh
java BlahBlah
Call this whatever you want, mv it to your /usr/local/bin directory, then just type it at
the command line and BlahBlah will be run.
Q: Are there any Java libraries for executing Linux commands?
Answer: Try java.lang.Runtime.exec(). E.g.
Runtime.getRuntime().exec("xterm");
Note if you want to use shell builtins or shell features like
redirection you need a shell, e.g.:
Runtime.getRuntime().exec(new String[] {"/bin/sh",
"-c", "ls / 2>&1 | tee ls.log"});
I'd like to know how to know which operating system java application is running
on.
Answer: You could try using the system Properties.
e.g.
Properties prop = System.getProperties();
String osString = prop.getProperty( "os.name" );
I would like to know how my Java program can catch when someone sends a
"kill" to my app in Unix or does a Ctrl-C in windows?
In Unix there is atexit() function that handles this type of situation. Is this possible in
Java ?
Answer: Starting with 1.3 there is Runtime.addShutdownHook(). This is for cleanup
only.
from API: "A shutdown hook is simply an initialized but unstarted thread. When the
virtual machine begins its shutdown sequence it will start all registered shutdown
hooks in some unspecified order and let them run concurrently. When all the hooks
have finished it will then run all uninvoked finalizers if finalization-on-exit has been
enabled.
Finally, the virtual machine will halt. Note that daemon threads will continue to run
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