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POWhy do I get "Exception; must be caught or declared to be thrown" when I try to compile my Java code?
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copied!<p>Consider:</p> <pre><code>import java.awt.*; import javax.swing.*; import java.awt.event.*; import javax.crypto.*; import javax.crypto.spec.*; import java.security.*; import java.io.*; public class EncryptURL extends JApplet implements ActionListener { Container content; JTextField userName = new JTextField(); JTextField firstName = new JTextField(); JTextField lastName = new JTextField(); JTextField email = new JTextField(); JTextField phone = new JTextField(); JTextField heartbeatID = new JTextField(); JTextField regionCode = new JTextField(); JTextField retRegionCode = new JTextField(); JTextField encryptedTextField = new JTextField(); JPanel finishPanel = new JPanel(); public void init() { //setTitle("Book - E Project"); setSize(800, 600); content = getContentPane(); content.setBackground(Color.yellow); content.setLayout(new BoxLayout(content, BoxLayout.Y_AXIS)); JButton submit = new JButton("Submit"); content.add(new JLabel("User Name")); content.add(userName); content.add(new JLabel("First Name")); content.add(firstName); content.add(new JLabel("Last Name")); content.add(lastName); content.add(new JLabel("Email")); content.add(email); content.add(new JLabel("Phone")); content.add(phone); content.add(new JLabel("HeartBeatID")); content.add(heartbeatID); content.add(new JLabel("Region Code")); content.add(regionCode); content.add(new JLabel("RetRegionCode")); content.add(retRegionCode); content.add(submit); submit.addActionListener(this); } public void actionPerformed(ActionEvent e) { if (e.getActionCommand() == "Submit"){ String subUserName = userName.getText(); String subFName = firstName.getText(); String subLName = lastName.getText(); String subEmail = email.getText(); String subPhone = phone.getText(); String subHeartbeatID = heartbeatID.getText(); String subRegionCode = regionCode.getText(); String subRetRegionCode = retRegionCode.getText(); String concatURL = "user=" + subUserName + "&f=" + subFName + "&l=" + subLName + "&em=" + subEmail + "&p=" + subPhone + "&h=" + subHeartbeatID + "&re=" + subRegionCode + "&ret=" + subRetRegionCode; concatURL = padString(concatURL, ' ', 16); byte[] encrypted = encrypt(concatURL); String encryptedString = bytesToHex(encrypted); content.removeAll(); content.add(new JLabel("Concatenated User Input -->" + concatURL)); content.add(encryptedTextField); setContentPane(content); } } public static byte[] encrypt(String toEncrypt) throws Exception{ try{ String plaintext = toEncrypt; String key = "01234567890abcde"; String iv = "fedcba9876543210"; SecretKeySpec keyspec = new SecretKeySpec(key.getBytes(), "AES"); IvParameterSpec ivspec = new IvParameterSpec(iv.getBytes()); Cipher cipher = Cipher.getInstance("AES/CBC/NoPadding"); cipher.init(Cipher.ENCRYPT_MODE, keyspec, ivspec); byte[] encrypted = cipher.doFinal(toEncrypt.getBytes()); return encrypted; } catch(Exception e){ } } public static byte[] decrypt(byte[] toDecrypt) throws Exception{ String key = "01234567890abcde"; String iv = "fedcba9876543210"; SecretKeySpec keyspec = new SecretKeySpec(key.getBytes(), "AES"); IvParameterSpec ivspec = new IvParameterSpec(iv.getBytes()); Cipher cipher = Cipher.getInstance("AES/CBC/NoPadding"); cipher.init(Cipher.DECRYPT_MODE, keyspec, ivspec); byte[] decrypted = cipher.doFinal(toDecrypt); return decrypted; } public static String bytesToHex(byte[] data) { if (data == null) { return null; } else { int len = data.length; String str = ""; for (int i=0; i<len; i++) { if ((data[i]&0xFF) < 16) str = str + "0" + java.lang.Integer.toHexString(data[i]&0xFF); else str = str + java.lang.Integer.toHexString(data[i]&0xFF); } return str; } } public static String padString(String source, char paddingChar, int size) { int padLength = size-source.length() % size; for (int i = 0; i < padLength; i++) { source += paddingChar; } return source; } } </code></pre> <p>I'm getting an unreported exception:</p> <pre><code>java.lang.Exception; must be caught or declared to be thrown byte[] encrypted = encrypt(concatURL); </code></pre> <p>As well as:</p> <pre><code>.java:109: missing return statement </code></pre> <p>How do I solve these problems?</p>

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