/** java Show filename : shows the content of the file */

import java.io.*;

public class Show {
    public static void main(String[] args) {
        String filename = null;   
        FileInputStream in = null; 
        
        if(args.length != 1) {
            System.out.println("Usage: java Show filename");
            System.out.println("Shows the file");
            return; // or System.exit(0);
        } else {
            filename = args[0];
            try { 
                in = new FileInputStream(filename);
            } catch (FileNotFoundException ex) {
                System.out.println(filename + " not found");
                return;
            }
            
            int ch;
            try {
               while((ch = in.read()) != -1) {
                   // process the char ch
                   System.out.print((char)ch);
               }
            } catch (IOException ex) {
                // do nothing
            }
            
            try {
                in.close();
            } catch (IOException ex) {
                // do nothing
            }            
       }
  }
}

import java.io.*;

public class FileOutTest {
    public static void main(String[] args) {
        char[] array = {'h', 'e', 'l', 'l', 'o'}; // hello
        String outFileName = "out.txt";
        FileOutputStream out = null;
        try {
            out = new FileOutputStream(outFileName);
        } catch (FileNotFoundException ex) {
            return; // stop the program, probably should print out an error message
        }
        
        try {
            for(int i = 0; i < array.length; i++) {
                 out.write(array[i]);
            }
        }  catch (IOException ex) {
            // do nothing
        }
          
        try {
            out.close();
        } catch (IOException ex) {
            // do nothing
        }
    }
}

import java.io.*;

public class CopyFile {
    public static void main(String[] args) {
        String inFileName, outFileName;
        FileInputStream in = null;
        FileOutputStream out = null;
        
        if(args.length != 2) {
            System.out.println("Usage: java CopyFile inFile outFile");
            System.out.println("copies inFile to outFile");
        } else {
            inFileName = args[0];
            outFileName = args[1];
            try {
                in = new FileInputStream(inFileName);
            } catch (FileNotFoundException ex) {
                System.out.println(inFileName + " not found");
                System.exit(0);
            }
            
            try {
                out = new FileOutputStream(outFileName);
            } catch (FileNotFoundException ex) {
                System.out.println("Can't open " + outFileName);
                System.exit(0);
            }
            
            try {
                int ch;
                while((ch = in.read()) != -1) {
                    out.write(ch);
                }
            } catch (IOException ex) {
                System.out.println("IOException");
            }
            
            // close all the stream
            try {
                in.close();
                out.close();
            } catch (IOException ex) {
                // do nothing
            }
        }
            
    }
}

import java.io.*;

public class CopyFile2 {
    public static void main(String[] args) throws Exception {
        String inFileName, outFileName;
        FileInputStream in = null;
        FileOutputStream out = null;
        
        if(args.length != 2) {
            System.out.println("Usage: java CopyFile2 inFile outFile");
            System.out.println("copies inFile to outFile");
        } else {
            inFileName = args[0];
            outFileName = args[1];
            in = new FileInputStream(inFileName);
            out = new FileOutputStream(outFileName);
           
            int ch;
            while((ch = in.read()) != -1) {
                out.write(ch);
            }
                
            in.close();
            out.close();

        }            
    }
}

import java.io.*;

/** the program creates a log table */
public class LogTable {
    public static void main(String[] args) {
        PrintStream out = null;
        int max = 10; 
        try {
            out = new PrintStream(new FileOutputStream("table"));
        } catch (FileNotFoundException ex) {
            System.exit(0);
        }
        
        // notice that no exception is thrown by print or println method
        for(int i = 1; i < max; i++) {
            out.println(i + "\t" + Math.log(i));
        }
        
        out.close();
    }
}

1	0.0
2	0.6931471805599453
3	1.0986122886681096
4	1.3862943611198906
5	1.6094379124341003
6	1.791759469228055
7	1.9459101490553132
8	2.0794415416798357
9	2.1972245773362196