Probable Prime using Java Big Integer

BigInteger prime = BigInteger.valueOf(0);
for (int i = 0; i < n; i++) {
    prime = prime.nextProbablePrime();
}
System.out.println(prime.intValue());

Most Efficient Code for Nth Prime

public static int nthprime(int n) {
if (n == 1) return 2;
if (n == 2) return 3;
int limit, root, count = 1;
limit = (int)(n * (Math.log(n) + Math.log(Math.log(n)))) + 3;
root = (int) Math.sqrt(limit) + 1;
limit = (limit - 1) / 2;
root = root / 2 - 1;
boolean[] sieve = new boolean[limit];
for (int i = 0; i < root; ++i) {
if (!sieve[i]) {
++count;
for (int j = 2 * i * (i + 3) + 3, p = 2 * i + 3; j < limit; j += p) {
sieve[j] = true;
}
}
}
int p;
for (p = root; count < n; ++p) {
if (!sieve[p]) {
++count;
}
}
return 2 * p + 1;
}

CSS Element Full Rotation

/* rotation animation */
@-webkit-keyframes rotate {
  from { -webkit-transform:rotate(0deg); }
  to { -webkit-transform:rotate(360deg); }
}

@-moz-keyframes rotate {
  from { -moz-transform:rotate(0deg); }
  to { -moz-transform:rotate(360deg); }
}

@-ms-keyframes rotate {
  from { -ms-transform:rotate(0deg); }
  to { -ms-transform:rotate(360deg); }
}

@-o-keyframes rotate {
  from { -o-transform:rotate(0deg); }
  to { -o-transform:rotate(360deg); }
}

.rotating {
  -webkit-transform-origin: 50% 50%;
  -webkit-animation-name: rotate;
  -webkit-animation-duration: 1s;
  -webkit-animation-iteration-count: infinite;
  -webkit-animation-timing-function: linear;
  -moz-transform-origin: 50% 50%;
  -moz-animation-name: rotate;
  -moz-animation-duration: 1s;
  -moz-animation-iteration-count: infinite;
  -moz-animation-timing-function: linear;
  -ms-transform-origin: 50% 50%;
  -ms-animation-name: rotate;
  -ms-animation-duration: 1s;
  -ms-animation-iteration-count: infinite;
  -ms-animation-timing-function: linear;
  -o-transform-origin: 50% 50%;
  -o-animation-name: rotate;
  -o-animation-duration: 1s;
  -o-animation-iteration-count: infinite;
  -o-animation-timing-function: linear;
}

Clean Up Email

[from:noreply* OR from:do-not-reply* OR from:donotreply* OR from:notification*]
[from:news* OR from:digest* OR from:auto* OR from:reports* OR from:*mailer*]

io to nio

File folder=new Folder("D:\\");

File[] files = folder.listFiles(new FilenameFilter() {
public boolean accept(File dir, String name) {
return name.toLowerCase().endsWith("" + FILE_EXT + "");
}
});

Path dir=Paths.get("D:\\");
DirectoryStream<Path> stream = Files.newDirectoryStream(dir, "*.{" + FILE_EXT + "}");

Base64

Base64.encodeBase64String(input.getBytes(charset));

Quick System.out.println()

static<T> void z(T arg) { System.out.println(arg); }
use z(object)
buzz around! dump text, write to console, overflow the terminal, debug code

Things to do on Fresh Linux installation

sudo apt-get install synaptic vlc gimp gimp-data gimp-plugin-registry gimp-data-extras y-ppa-manager bleachbit openjdk-7-jre oracle-java8-installer flashplugin-installer unace unrar zip unzip p7zip-full p7zip-rar sharutils rar uudeview mpack arj cabextract file-roller libxine1-ffmpeg mencoder flac faac faad sox ffmpeg2theora libmpeg2-4 uudeview libmpeg3-1 mpeg3-utils mpegdemux liba52-dev mpeg2dec vorbis-tools id3v2 mpg321 mpg123 libflac++6 totem-mozilla icedax lame libmad0 libjpeg-progs libdvdcss2 libdvdread4 libdvdnav4 libswscale-extra-2 ubuntu-restricted-extras ubuntu-wallpapers*

1. synaptic is a package manager, which we use in many tutorials.
2. vlc is one of the most popular and powerful media players available.
3. gimp, gimp-data, gimp-plugin-registry, andgimp-data-extras are all parts of a powerful photo editor, built to rival Adobe Photoshop.
4. y-ppa-manager is there so you can manage PPAs without needing to use the Terminal.
5. bleachbit is a powerful cleaning utility.
6. openjdk-7-jre is an open-source Java emulator.
7. oracle-java8-installer is the official Java installer.
8. flashplugin-installer is the official Flash installer.
9. unace, unrar, zip, unzip, p7zip-full, p7zip-rar, sharutils, rar, uudeview, mpack, arj,cabextract, and file-roller are there to extract and compress files in various archive formats.
10. libxine1-ffmpeg, mencoder, flac, faac, faad,sox, ffmpeg2theora, libmpeg2-4, uudeview,libmpeg3-1, mpeg3-utils, mpegdemux, liba52-dev, mpeg2dec, vorbis-tools, id3v2, mpg321,mpg123, libflac++6, totem-mozilla, icedax,lame, libmad0, libjpeg-progs, libdvdcss2,libdvdread4, libdvdnav4, libswscale-extra-2and ubuntu-restricted-extras are all media codecs. They play videos, music, and DVDs.
11. ubuntu-wallpapers* adds basically every wallpaper that has ever lived.

Exploring java.time package

Forget Java.Date and Java.Calendar,
try Java.Time!

Source Code

//生年月日
LocalDate bf=LocalDate.of(1992,12,16);
LocalDate rf=LocalDate.of(2015,12,19);
Clock c=Clock.systemUTC();
Clock d=Clock.systemDefaultZone();
LocalDate n=LocalDate.now();//c or d
dump("Current Instant : "+Instant.now());
dump("Current Instant as per System UTC: "+Instant.now(c));
dump("Current Instant as per System Default Timezone : "+Instant.now(d));
dump("Birthdate -> "+bf);
dump("DoM : " +bf.getDayOfMonth()+" of "+bf.lengthOfMonth()+"-day long "+bf.getMonth());
dump("DoY : "+bf.getDayOfYear()+" of "+bf.lengthOfYear()+"-day long "+bf.getYear());
dump("Today -> "+n);
Period yet=bf.until(n);//Duration equivalent in terms of Days
//年齢
dump("Age : -> "+yet.getYears()+" years "+yet.getMonths()+" months "+yet.getDays()+" days");
dump("Today -> "+n);
dump("Flight -> "+rf);
Period more=n.until(rf);//Try Duration for time to sleep, go home or wake up.
dump("Return : -> "+more.getYears()+" years "+more.getMonths()+" months "+more.getDays()+" days");

Wet Run - Sample Output

Current Instant : 2015-05-18T07:55:55.178Z
Current Instant as per System UTC: 2015-05-18T07:55:55.192Z
Current Instant as per System Default Timezone : 2015-05-18T07:55:55.192Z
Birthdate -> 1992-12-16
DoM : 16 of 31-day long DECEMBER
DoY : 351 of 366-day long 1992
Today -> 2015-05-18
Age : -> 22 years 5 months 2 days
Today -> 2015-05-18
Flight -> 2015-12-19
Return : -> 0 years 7 months 1 days

Common Regular Expressions

IP Address Regexp

\b(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\b

MAC Address Regexp

^([0-9a-fA-F][0-9a-fA-F]:){5}([0-9a-fA-F][0-9a-fA-F])$



Domain Name Regexp

^([a-zA-Z0-9]([a-zA-Z0-9\-]{0,61}[a-zA-Z0-9])?\.)+[a-zA-Z]{2,6}$



Floating Point Number Regexp

[-+]?(?:\b[0-9]+(?:\.[0-9]*)?|\.[0-9]+\b)(?:[eE][-+]?[0-9]+\b)?



Roman Number Regexp

^(?i:(?=[MDCLXVI])((M{0,3})((C[DM])|(D?C{0,3}))?((X[LC])|(L?XX{0,2})|L)?((I[VX])|(V?(II{0,2}))|V)?))$