Bubble sort

/*
 *Write a program to implement bubble sort on a list of names and numbers according to user's choice
 */
import java.io.*;
class bubble_sort
{
public void main()throws IOException
{
BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
System.out.println("Enter your choice \n 1.Sorting names \n 2.Sorting numbers");
int ch=Integer.parseInt(br.readLine());
switch(ch)
{
case 1:System.out.println("Enter number of names");
int n=Integer.parseInt(br.readLine());
String s[]=new String[n];
System.out.println("Enter names");
for(int i=0;i<n;i++)
s[i]=br.readLine();
String temp="";
for(int i=0;i<n-1;i++)
{
for(int j=0;j<n-i-1;j++)
{
if(s[j].compareTo(s[j+1])>0)
{
temp=s[j];
s[j]=s[j+1];
s[j+1]=temp;
}}}
System.out.println("Sorted array");
for(int i=0;i<n;i++)
System.out.println(s[i]+" ");
break;
case 2:System.out.println("Enter number of numbers");
int x=Integer.parseInt(br.readLine());
double a[]=new double[x];
System.out.println("Enter numbers");
for(int i=0;i<x;i++)
a[i]=Double.parseDouble(br.readLine());
double temp2;
for(int i=0;i<x-1;i++)
{
for(int j=0;j<x-i-1;j++)
{
if(a[j]>a[j+1])
{
temp2=a[j];
a[j]=a[j+1];
a[j+1]=temp2;
}}}
System.out.println("Sorted array");
for(int i=0;i<x;i++)
System.out.println(a[i]+" ");
break;
default:System.out.println("Wrong choice");
}}}