java-one-liners

Libraries to include

• Apache commons-lang(3)
• Apache commons-collections
• Apache commons-io
• Apache commons-codec
• Apache commons-are-you-noticing-a-trend-yet ...
• Google Guava

IDE Shortcuts

If you are using Eclipse, you can add many of the following static utility classes as favorites.

• Preferences > Java > Editor > Content Assist > Favorites
• Add New Type
• Type in the name of the class, such as org.apache.commons.lang3.StringUtils
• OK
• Back in an editor window, type the name of one of the methods minus the class name, such as isBlank (from StringUtils), and invoke code completion (CTRL+Space on Windows) - you should see StringUtils.join as the first choice in the code completion popup.

Strings

// org.apache.commons.lang3.RandomStringUtils
RandomStringUtils.randomAlphabetic(10);     //ajsdiqdIQq
RandomStringUtils.randomNumeric(10);        //1928912391
RandomStringUtils.randomAlphaNumeric(10);   //698jd19dn1

//org.apache.commons.lang3.text.WordUtils
WordUtils.capitalize("hello WORLD");        //Hello WORLD
WordUtils.uncapitalize("hello WORLD");      //hello wORLD
WordUtils.capitalizeFully("hello WORLD");   //Hello World
WordUtils.initials("hello WORLD");          //hW

//org.apache.commons.lang3.CharSetUtils
CharSetUtils.keep("(555) 555-1212","1234567890"); //5555551212 - String a phone number of all but digits

// org.apache.commons.codec.digest.DigestUtils
DigestUtils.shaHex("hello world");          //2aae6c35c94fcfb415dbe95f408b9ce91ee846ed

//com.google.common.hash.Hashing
Hashing.sha1().hashString("hello world").toString(); //2aae6c35c94fcfb415dbe95f408b9ce91ee846ed

//org.apache.commons.lang3.StringUtils
StringUtils.isBlank(null);                  //true
StringUtils.isBlank("");                    //true
StringUtils.isBlank("   ");                 //true
StringUtils.isBlank("\t\t");                //true
StringUtils.isBlank("Something");           //false
StringUtils.isNotBlank("Something");        //true
StringUtils.isEmpty(null);                  //true
StringUtils.isEmpty("");                    //true
StringUtils.isEmpty("   ");                 //false
StringUtils.isEmpty("\t\t");                //false
StringUtils.isEmpty("Something");           //false
StringUtils.isNotEmpty("Something");        //true
StringUtils.join(new String[]{"A","B","C"},", "); //"A, B, C"

Collections

//java.util.Arrays
//Create an Immutable List
List<String> myList = Arrays.asList("A","B","C");

//java.util.Collections
//Sort a List in place
Collections.sort(myList);

//Reverse a List
Collections.reverse(myList);

//Randomize a List
Collections.shuffle(myList);

//Create am immutable collection of one item
Set<String> set = Collections.singleton("Value");
List<String> list = Collections.singletonList("Value");
Map<String,String> map = Collections.singletonMap("Key","Value");

//Wrap a collection so that it is immutable
Collection<String> immutable = Collections.unmodifiableCollection(myList);

//Apache commons-collections
CollectionUtils.isEmpty(null);                //true
CollectionUtils.isEmpty(emptyArray);          //true
CollectionUtils.isEmpty(Arrays.asList("A"));  //false

//Google Guava Collections
//com.google.common.collect.Lists
List<String> l = Lists.newArrayList("A","B","C"); //Mutable
List<List<String>> lol = Lists.partition(Lists.newArrayList("A","B","C","D"), 2); // Creates [[A,B],[C,D]]

IO

//org.apache.commons.io.FileUtils
List<String> lines = FileUtils.readLines(new File("/tmp/test.txt"));
FileUtils.writeLines(new File("/tmp/test.txt"), Arrays.asList("A","B","C"));
String contents = FileUtils.readFileToString(new File("/tmp/test.txt"));

//org.apache.commons.io.IoUtils
IOUtils.closeQuietly(inputStream);      //Close an input stream without throwing an IOException
HexDump.dump(data, 0, System.out, 0);   //Write a hex dump of data (byte[]) to System.out

Objects

//One-line replacement for overridden equals() and hashCode() methods:
//org.apache.commons.lang3.builder.EqualsBuilder
EqualsBuilder.reflectionEquals(this,other);
//org.apache.commons.lang3.builder.HashCodeBuilder
HashCodeBuilder.reflectionHashCode(this);