Thread: Uppercase and Lowercase in a string

Hi, my name is shane. The program is about determining if a character is upper or lower case and reversing it. The program does convert AbC to aBc but it will not convert if the same character in the string. It will convert the first character to the opposite case and apply it to the rest of the letters. For example, aBcb will convert to AbCb or AbCB will convert to ABCB. Below is my code. Any suggestions will be appreciated.

HTML Code:

private class CalculateButtonHandler implements ActionListener
   {
      //create convert button action
      public void actionPerformed(ActionEvent e)
      {
    	  //declare variables
    	  int i;
    	  String str;

              //get string from text field
              str = string1TF.getText();
      
             //loop through string
             for (i = 0; i < str.length(); i++)
               {

        	   //determine if character is upper or lower and reverse
        	 if
        	(str.charAt(i) == Character.toUpperCase(str.charAt(i)))
             str = str.replace(str.charAt(i), Character.toLowerCase(str.charAt(i)));
        	
             else 
            	 str = str.replace(str.charAt(i), Character.toUpperCase(str.charAt(i)));
        		 
                }
         
         	//show result
        	string2TF.setText(str);
      }
   }