Thread: Why does my calculator only return 0.0?

I am making a calculator in Java. However, when I press the "=" button on my calculator, it always returns 0.0, no matter what. I don't understand why? The code is below:

import javax.swing.*;//import the packages needed for gui
import java.awt.*;
import java.awt.event.*;
import java.util.Arrays;
import java.util.List;
import static java.lang.Math.*;
public class CalculatorCopy {
    public static void main(String[] args) {
	JFrame window = new JFrame("Window");//makes a JFrame
	    window.setSize(300,415); 
	window.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
	JPanel panel = new JPanel (new FlowLayout());//makes the panel, textfield and buttons and gives the buttons actioncommands
    final JTextField textField = new JTextField(20);
	JButton openbracket = new JButton("(");
		openbracket.setActionCommand("(");
	JButton closebracket = new JButton(")");
	closebracket.setActionCommand(")");
	JButton clearbutton = new JButton("C");
	clearbutton.setActionCommand("C");
	JButton arcsin = new JButton("arcsin");
	arcsin.setActionCommand("arcsin");
	JButton arccos = new JButton("arccos");
	arccos.setActionCommand("arccos");
	JButton arctan = new JButton("arctan");
	arctan.setActionCommand("arctan");
	JButton sin = new JButton("sin");
	sin.setActionCommand("sin");
	JButton cos = new JButton("cos");
	cos.setActionCommand("cos");
	JButton tan = new JButton("tan");
	tan.setActionCommand("tan");
	JButton log = new JButton("log");
    log.setActionCommand("log");
	JButton seven = new JButton("7");
	seven.setActionCommand("seven");
	JButton eight = new JButton("8");
	eight.setActionCommand("eight");
	JButton nine = new JButton("9");
	nine.setActionCommand("nine");
	JButton four = new JButton("4");
	four.setActionCommand("four");
	    JButton five = new JButton("5");
	    five.setActionCommand("five");
	    JButton six = new JButton("6");
	    six.setActionCommand("six");
	    JButton one = new JButton("1");
	    one.setActionCommand("one");
	    JButton two = new JButton("2");
	    two.setActionCommand("two");
	    JButton three = new JButton("3");
	    three.setActionCommand("three");
	    JButton zero = new JButton("0");
	    zero.setActionCommand("zero");
	    JButton radixpoint = new JButton(".");
	    radixpoint.setActionCommand("radixpoint");
	    JButton plus = new JButton("+");
	    plus.setActionCommand("plus");
	    JButton subtract = new JButton("-");
	    subtract.setActionCommand("subtract");
	    JButton multiply = new JButton("x");
	    multiply.setActionCommand("multiply");
	    JButton divide = new JButton("/");
	    divide.setActionCommand("divide");
	    JButton equal = new JButton("=");
	    equal.setActionCommand("equal");
	    final String values = " ";
	    class Listener implements ActionListener {	
	    	String out = "";
	     public void actionPerformed(ActionEvent e) {   		  
		    String output = e.getActionCommand();
		    if(output == "(") {
               out = out + "(";
               textField.setText(out);   
		    } else if (output == ")") {
		    out = out + ")";
		    textField.setText(out);	
		    }	else if (output == "C") {
		    	textField.setText(" ");
		    	out = "";
		    }  else if (output == "arcsin") {
		    	out = out + "asin(";
		    	textField.setText(out);	
		    }	else if (output == "arccos") {
		    	out = out + "acos(";
		    	textField.setText(out);
		    }	 else if (output == "arctan") {
		    	out = out + "atan(";
		    	textField.setText(out);
		    }   else if (output == "log") {
		    	out = out + "log(";
		    	textField.setText(out);	
		    }   else if (output == "seven") {
		    	out = out + "7";
		    	textField.setText(out);
		    }   else if (output == "eight") {
		    	out = out + "8";
		    	textField.setText(out);
		    }   else if (output == "nine") {
		    	out = out + "9";
		    	textField.setText(out);
		    }   else if (output == "four") {
		    	out = out + "4";
		    	textField.setText(out);
		    }   else if (output == "five") {
		    	out = out + "5";
		    	textField.setText(out);
		    }   else if (output == "six") {
		    	out = out + "6";
		    	textField.setText(out);
		    }   else if (output == "one") {
		    	out = out + "1";
		    	textField.setText(out);
		    }   else if (output == "two") {
		    	out = out + "2";
		    	textField.setText(out);
		    }   else if (output == "three") {
		    	out = out + "3";
		    	textField.setText(out);
		    }   else if (output == "zero") {
		    	out = out + "0";
		    	textField.setText(out);
		    }   else if (output == "radixpoint") {
		    	out = out + ".";
		    	textField.setText(out);
		    }   else if (output == "equal") {
		    	String[] numbers = out.split("[ +-x/doublesintarclg]", 0); //separate the numbers from the operations
		    	String[] operations = out.split("[ 1234567890.()]", 0);
		    	double[] realnumbers = new double[100]; //make an array of doubles
		    	double answer = 0;
		    	for ( String number: numbers ) {
		    	for (double realnumber : realnumbers ) {
		    	realnumber =  Double.parseDouble(number); //make the string number a double value
		    	}		
		    	}	
                for (String op : operations ) {
                	if (op == "x") {
                	  answer = answer + realnumbers[Arrays.asList(operations).indexOf(op)]*realnumbers[Arrays.asList(operations).indexOf(op)+1]; 
                	}
                	if (op == "/") {
                	answer = answer + realnumbers[Arrays.asList(operations).indexOf(op)]/realnumbers[Arrays.asList(operations).indexOf(op)+1];
                	}
                	if (op == "+") {
                	answer = answer + realnumbers[Arrays.asList(operations).indexOf(op)]+realnumbers[Arrays.asList(operations).indexOf(op)+1];	
                	}
                	if (op == "-") {
                	answer = answer + realnumbers[Arrays.asList(operations).indexOf(op)]-realnumbers[Arrays.asList(operations).indexOf(op)+1];
                	}
                	String stringofanswer = String.valueOf(answer);
                	textField.setText(stringofanswer);
 
                }
		    }   else if (output == "plus") {
		    	out = out + "+";
		    	textField.setText(out);
		    }   else if (output == "subtract") {
		    	out = out + "-";
		    	textField.setText(out);
		    }   else if (output == "multiply") {
		    	out = out + "x";
		    	textField.setText(out);
		    }   else if (output == "divide") {
		    	out = out + "/";
		    	textField.setText(out);
		    }
		}
	}
	Listener listener = new Listener(); //makes an object of the actionlistener
 panel.add(textField);//adding all the things
	    window.add(panel);
	openbracket.addActionListener(listener);    
	panel.add(openbracket);
	closebracket.addActionListener(listener);
	panel.add(closebracket);
	clearbutton.addActionListener(listener);
	panel.add(clearbutton);
	arcsin.addActionListener(listener);
	panel.add(arcsin);
	arccos.addActionListener(listener);
	panel.add(arccos);
	arctan.addActionListener(listener);
	panel.add(arctan);
	sin.addActionListener(listener);
	panel.add(sin);
	cos.addActionListener(listener);
	panel.add(cos);
	tan.addActionListener(listener);
	panel.add(tan);
	log.addActionListener(listener);
	panel.add(log);
	nine.addActionListener(listener);
	panel.add(nine);
	eight.addActionListener(listener);
	panel.add(eight);
	seven.addActionListener(listener);
	panel.add(seven);
	six.addActionListener(listener);
	panel.add(six);
	five.addActionListener(listener);
	panel.add(five);
	four.addActionListener(listener);
	panel.add(four);
	three.addActionListener(listener);
	panel.add(three);
	two.addActionListener(listener);
	panel.add(two);
	one.addActionListener(listener);
	panel.add(one);
	zero.addActionListener(listener);
	panel.add(zero);
	radixpoint.addActionListener(listener);
	panel.add(radixpoint);
	plus.addActionListener(listener);
	panel.add(plus);
	subtract.addActionListener(listener);
	panel.add(subtract);
	multiply.addActionListener(listener);
	panel.add(multiply);
	divide.addActionListener(listener);
	panel.add(divide);
	equal.addActionListener(listener);
	panel.add(equal);
	window.setVisible(true);
}
}

What's wrong with my code?