Error message "unreported exception java.io.IOException; must be caught or declared to be thrown"

Question

Error:

filecontent.java:15: unreported exception java.io.IOException; must be caught or declared to be thrown

showfile(); ^ filecontent.java:78: unreported exception java.io.IOException; must be caught or declared to be thrown

showfile(); ^

I have already thrown java.io.IOException, but still it shows these errors.

My code:

import java.awt.*; import java.awt.event.*; import java.io.*;  class filecontent extends Frame implements ActionListener {     TextField t[] = new TextField[4];     TextArea ta[] = new TextArea[4];     Button submit;     Panel p1;     filecontent()     {         setGUI();         setRegister();         showfile();         setTitle("FileData");         setVisible(true);         setSize(300, 300);         /*  addWindowListener(new WindowAdapter()             {                  public void windowClosing(WindowEvent we)                 {                      System.exit(0);                  }             });          */      }      void setGUI()     {         p1 = new Panel();         p1.setLayout(new GridLayout(5, 4, 10, 10));         for(int i=0; i<4; i++)         {             t[i] = new TextField(10);             ta[i] = new TextArea("");             p1.add(t[i]);             p1.add(ta[i]);         }         submit = new Button("Submit");         p1.add(submit);     }      void setRegister()     {         submit.addActionListener(this);     }      void showfile() throws java.io.IOException     {         FileReader fin[] = new FileReader[4];         FileReader fn;         //   br[]=new BufferedReader[4];          for(int i=0;i<4;i++)         {             fin[i]=new FileReader(t[i].getText());         }         int cnt = 1;         String s;         fn = fin[0];         BufferedReader br = new BufferedReader(fn);         while(cnt <= 4)         {             if((s=br.readLine()) != null)             {                 ta[cnt-1].append(s+"");             }             else             {                 cnt++;                 fn = fin[cnt-1];                 ta[cnt-1].setText("");             }         }     }      public void actionPerformed(ActionEvent ae)     {         if(ae.getSource()==submit)         {             showfile();         }     }      public static void main(String ar[])     {         new filecontent();     } } 

Answer 1

void showfile() throws java.io.IOException  <----- 

Your showfile() method throws IOException, so whenever you use it you have to either catch that exception or again thorw it. Something like:

try {   showfile(); } catch(IOException e) {   e.printStackTrace(); } 

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You should learn about exceptions in Java.