Java Solutions: Console

Friday, May 16, 2014

NetBeans - Throwable.printStackTrace() should be removed

If you use NetBeans for your Java development, whenever you use printStackTrace() in a catch block, you get a warning sign that the Throwable.printStackTrace() should be removed.

To get rid of this warning sign, do one of the followings

1. Log the exception. For example to log to a file.
Logger logger = Logger. getAnonymousLogger();
logger.addHandler(new FileHandler("<directory>/<file name>");
logger.log(Level.SEVERE, <exception>.getMessage(), <exception>);

2. Print the stack trace to a file
PrintStream ps = new PrintStream(
new FileOutputStream("<directory>/<file name>", true));
<exception>.printStackTrace(ps);

3. If your really want to print to the console, use <exception>.printStackTrace(System.out) instead of <exception>.printStackTrace()

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Tuesday, May 6, 2014

Read from and write to the command line in Java

A. Read from the command line

1. The Scanner
Scanner theScanner = new Scanner(System.in);
if (theScanner.hasNextLine()) {
String input = theScanner.nextLine();
}

2. The BufferedReader and the InputStreamReader
BufferedReader theReader = new BufferedReader(
new InputStreamReader(System.in));
String line = theReader.readLine();

3. The Console
Console theConsole = System.Console();
if (theConsole != null) {
String line = theConsole.readLine();
char[] password = theConsole.readPassword("Enter your password: ");
............
Arrays.fill(password, ' ');
}

B. Write to the command line

1. The System.out
System.out.println("The word to write");

2. The Console
Console theConsole = System.Console();
if (theConsole != null) {
theConsole.format("Enter 1 to continue, 2 to exit");
}

References:

1. I/O from the Command Line

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