Java Tricks

Installing Sun Java 6 on Ubuntu 10.10

To install Sun's Java 6 JDK on Ubuntu 10.10, add the Sun Java6 Community PPA and install: # http://java.dzone.com/articles/sun-java-6-ubuntu-1004-1010

add-apt-repository ppa:sun-java-community-team/sun-java6
apt-get update
apt-get install sun-java6-jdk
update-java-alternatives -s java-6-sun

Output of bytes in hex

Here are 3 different ways to do the same thing.

   public static void main(String[] args) {
        // TODO code application logic here
        byte b1 = 77;
        byte b2 = -77;
        System.out.println("toHexString " + Integer.toHexString(b1));
        System.out.println("toHexString " + Integer.toHexString(b2));
        System.out.println("toHexString " + Integer.toHexString(b2 & 0xff));
        System.out.println("substring " + Integer.toString( ( b1 & 0xff ) + 0x100, 16).substring( 1 ));
        System.out.println("substring " + Integer.toString( ( b2 & 0xff ) + 0x100, 16).substring( 1 ));
        System.out.println("format " + String.format("%1$02X", b1));
        System.out.println("format " + String.format("%1$02X", b2));
    }

toHexString 4d
toHexString ffffffb3
toHexString b3
substring 4d
substring b3
format 4D
format B3

Turning up the StdOut? logging

import java.io.IOException;
import java.util.logging.*;

public class test {

    public static void main(String args[]) throws InterruptedException, IOException {

        LogManager.getLogManager().reset();

        Logger _LOGGER = Logger.getLogger(Logger.GLOBAL_LOGGER_NAME);
        _LOGGER.setLevel(Level.FINEST);

        ConsoleHandler ch = new ConsoleHandler();
        ch.setLevel(Level.FINEST);
        _LOGGER.addHandler(ch);        

        FileHandler fh = new FileHandler("scrvi-%u.log");
        fh.setFormatter(new SimpleFormatter());
        fh.setLevel(Level.FINEST);
        _LOGGER.addHandler(fh);
        fh.setLevel(Level.FINEST);

        _LOGGER.info("Loading Properties " + _LOGGER.getLevel());
        _LOGGER.finest("FINEST");
        _LOGGER.severe("SEVERE");
    }
}