Basic String Manipulation,removal of last character in While loop
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I am struggling with this basic code below ,

how do i prevent the last comma "," from being appended to the String.

		String outScopeActiveRegionCode="";
                	
		List<String> activePersons=new ArrayList<String>();
                	
        HashSet<String> outScopeActiveRegionCodeSet=new HashSet<String>();
                	
        for (String person : activePersons) {
	           				
           outScopeActiveRegionCodeSet.add(person); 
	           				           	
		}
           Iterator itr = outScopeActiveRegionCodeSet.iterator();

           		 while(itr.hasNext()){
           			outScopeActiveRegionCode+=itr.next();
           			outScopeActiveRegionCode+=",";
           		 }