/* http://stackoverflow.com/q/32878239/5290909 */
 
import java.util.*;
import java.lang.*;
import java.io.*;
import java.util.regex.*;
 
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
		String text = "@foo 12a@cat123-_     @dog123__-   @###aaa #@bar";
		Pattern p = Pattern.compile("(?<![-\\w])@[-\\w]+");
		Matcher m = p.matcher(text);
 
		while(m.find()){
		   String s = m.group();
		   System.out.println(s);
		}
	}
}

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