Please Help Me Find The Error.

In the Following Simple programs im getting a common error. missing return statement. Please help me find the repeated error committed by me.

program 1:

        import java.io.*;

        class jugal
        {
        int i,j;
        /* jugal(int i,int j)
        {
        this.i=i;
        this.j=j;
        }*/

        public int disp(int i,int j)
        {
        this.i=i;
        this.j=j;
        return i+j;
        }
        }

        class sample
        {
        public static Void main(String a1[])
        {
        jugal j1=new jugal();
        System.out.println(j1.disp(5,5));
        int a=Integer.parseInt(a1[0]);
        int b=Integer.parseInt(a1[1]);
        jugal j2=new jugal();
        int c=j2.disp(a,b);
        System.out.println("show" +c);
        }
        }

Code (markup):

program 2:

        interface example
        {
        final int a=5;
        Void show();
        }

        class jugal implements example
        {
        public Void show()
        {
        System.out.println(a*a);
        }

        }

        class sample1
        {
        public static Void main(String a1[])
        {
        jugal j1=new jugal();
        j1.show();
        }
        }

Code (markup):

program 3:

        class jugal implements Runnable
        {
        Thread t;
        jugal()
        {
        t=new Thread(this,"demo");
        System.out.println(t);
        t.start();
        }
        public Void run()
        {
        try
        {
        for(int i=1;i<10;i--);
        {
        System.out.println(i);
        Thread.sleep(500);
        }
        }
        catch(InterruptedException e)
        {
        System.out.println(e);
        }
        }
        }

        class sample2
        {
        public static Void main(String a[])
        {
        new jugal();
        try
        {
        for(int i=1;i<10;i--);
        {
        System.out.println(i);
        Thread.sleep(1000);
        }
        }
        catch(InterruptedException e)
        {
        System.out.println(e);
        }
        }
        }

Code (markup):

program 4:

        import java.util.*;

        public class sample5
        {
        public static Void main(String a[])
        {
        int c[]={5,7,1,3,2};
        Set<Integer> s=new HashSet<Integer>();

        for(int i=0;i<5;i++)
        {
        s.add(c[i]);
        }
        System.out.println(s);

        TreeSet ss=new TreeSet<Integer>(s);
        System.out.println(ss.first());
        System.out.println(ss.last());

        }
        }

Code (markup):

program 5:

        import java.util.*;

        public class sample6
        {
        public static Void main(String a[])
        {
        int c[]={4,6,2,1,9};
        List<Integer> l=new ArrayList<Integer>();

        for(int i=0;i<5;i++)
        {
        l.add(c[i]);
        }
        System.out.println(c);

        LinkedList<Integer> l1=new LinkedList<Integer>(l);

        for(int i=0;i<5;i++)
        {
        l1.addFirst(c[i]);
        }
        System.out.println(l1.removeLast());
        }
        }

Code (markup):

program 6:

        import java.util.*;

        public class sample7
        {
        public static Void main(String a[])
        {
        String s[]={"sun","mon","tues","wed","thrus"};

        Map m=new HashMap();
        for(int i=0;i<5;i++)
        {
        m.put(i,s[i]);
        }
        TreeMap t=new TreeMap(m);
        System.out.println(t.keySet());
        System.out.println(t.firstkey()+" value: "+t.get(t.firstKey()));
        System.out.println(t.lastKey()+" "+t.get(t.lastKey()));
        System.out.println(t.remove(t.lastkey()));
        System.out.println(t.values());
        System.out.println(t.keySet());
        }
        }

Code (markup):

program 7:

        import java.util.Vector;
        import java.util.Enumeration;

        class sample8
        {
        public static Void main(String a[])
        {
        Vector<Object> v=new Vector<Object>();
        int p=20;
        Integer i=new Integer(20);
        String s=new String("Jugal");
        v.add(i);
        v.add(p);
        v.add(s);
        System.out.println(v);
        v.add(2,new Integer(10));
        System.out.println(v);
        System.out.println(v.elementAt(2));
        System.out.println(v.firstElement());
        System.out.println(v.lastElement());
        v.removeElementAt(2);
        System.out.println(v);
        System.out.println(v.firstElement());
        System.out.println(v.lastElement());
        Enumeration e=v.elements();
        while(e.hasMoreElements())
        {
        System.out.println(e.nextElement());
        }
        }
        }

Code (markup):

 

Where are you getting the error? Give us some help here.

 

Error Has been rectified. void() func was written as Void().