TecSinapse DOJO -> One solution for the anagram's problem, using Groovy.

Anagram.groovy

package br.com.tecsinapse.dojo

class Anagram {
	
	def static anagram ( word ) {
		// If the word has the size 1 it is itself the anagram, otherwise I want the permutations
		return (word?.size() == 1) ? [ word ] : permutation( word )
	}	
	
	def static permutation ( word ) {
		if (word?.size() == 2) { // If the word has the size 2
			// I know how to do the permutation!
			[ "${word[0]}${word[1]}", "${word[1]}${word[0]}" ]
		} else { // otherwise I will
			def permutations = [] // create a list of permutations
			word.each { character -> // and fix a character of the word
				// then get the permutation of the word without the character
				permutation( word - character ).each { interchange -> // and for each interchange I will
					permutations << "${character}${interchange}" // add the new permutation
				}
			}
			permutations
		}
	}
}

Anagram.anagram("biro");

Anagram2.groovy

package br.com.tecsinapse.dojo

class Anagram2 {

	def static anagram ( word ) {
		def permutation = []
		if ( word?.size() > 0 ) {
			word?.collect { character ->
				character
			}.eachPermutation { interchange ->
				permutation << interchange.join( "" )
			}
		}
		return permutation
	}
}

Anagram2.anagram("biro");

Anagram3.groovy

package br.com.tecsinapse.dojo

String.metaClass.anagram << {
	def permutation = []
	if ( size() > 0 ) {
		delegate.collect { character ->
			character
		}.eachPermutation { interchange ->
			permutation << interchange.join( "" )
		}
	}
	return permutation
}

"biro".anagram()