Can anybody please help me debugging this code?

Solution.java:7: error: '{' expected
public class bubbleSort(int[] a) {
                       ^
Solution.java:7: error: ';' expected
public class bubbleSort(int[] a) {
                               ^
Solution.java:9: error: illegal start of expression
        public bubbleSort(int[] a){
        ^
Solution.java:9: error: '.class' expected
        public bubbleSort(int[] a){
                                ^
Solution.java:9: error: ';' expected
        public bubbleSort(int[] a){
                                 ^
Solution.java:56: error: reached end of file while parsing
}
 ^
6 errors

import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class bubbleSort(int[] a) {
        
        public bubbleSort(int[] a){
        int endPosition = a.length - 1;
        int swapPosition;

        while( endPosition > 0 ) {
            swapPosition = 0;
            swapNum =0;

            for(int i = 0; i < endPosition; i++) {

                if( a[i] > a[i + 1] ){
                    // Swap elements 'i' and 'i + 1':
                    int tmp = a[i];
                    a[i] = a[i + 1];
                    a[i + 1] = tmp;

                    swapPosition = i;
                    swapNum++;
                } 

                
            } 

            
        } 

        
        firstElement = a[0];
        lastElement = a[a.length -1];
        System.out.println("Array is sorted in "+ swapNum + " swaps.");
        System.out.println("First Element: "+ firstElement);
        System.out.println("Last Element: "+ lastElement);
    }
 } // end bubbleSort

public class Solution {
     
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        int[] a = new int[n];
        for(int a_i=0; a_i < n; a_i++){
            a[a_i] = in.nextInt();
        }
        
        bubbleSort instance = new bubbleSort(a);
        instance(a);
    }
}